PPA 1: Chemical Control of Turfgrass Diseases 2017

Transcript

1 PPA-1 iversity of K Un entucky College of Agricultur e, Food and Environmen t ative Extension Service oper Co Chemical Control of Turfgrass Diseases 2017 Paul Vincelli, Department of Plant Pathology, University of Kentucky; Bruce Clarke, Department of Plant Biology, Rutgers University; Gregg Munshaw, Department of Plant and Soil Sciences, University of Kentucky urfgrasses under intensive management are often subject fungicides may be applied to foliage If disease is not yet evident, to outbreaks of infectious diseases. Diseases usually are T that is either wet or dry. (In either case, wearing impermeable most damaging when weather or cultural conditions favor the boots is recommended.) disease-causing agent but not plant growth and vigor. Cultural If disease is already active: conditions that predispose turfgrass to diseases include close y For control of foliar diseases, apply the fungicide when foliage mowing, inadequate or excessive nitrogen fertility, light or is wet so that it sticks to leaf blades. frequent irrigation, excessive thatch, poor drainage, and shade. y For control of root diseases, either apply it to dry foliage, or Good turf management practices often greatly reduce the apply it to wet foliage followed by immediate, light irrigation impact of disease by promoting healthy plants that are better to wash the product into the topmost soil layer. able to resist infections. Even under good management, however, Contact and Systemic Fungicides diseases sometimes cause excessive damage to highly managed turfgrasses. The proper use of fungicides in these instances, There are two general types of fungicides. Contact fungicides, in conjunction with implementing best cultural management - sometimes called protectant fungicides, remain on plant sur practices that promote quality turf, can be an important part faces after application and do not penetrate the plant tissue. of an overall disease-management program. Systemic fungicides are those that are absorbed into the plant. Fungicides available for controlling turfgrass diseases in Ken - Some systemic fungicides move within the plant only a short tucky, New Jersey, and many other states are listed in Tables 1 distance from the site of penetration; these fungicides are and 2. Specific application rates, safety precautions, and other called locally systemic. The dicarboximide fungicides are one - important information are provided on the labels of the for example of this group. Some locally systemic fungicides simply mulated products. Read these labels completely and carefully cross the leaf blade from one leaf surface to the other but do before using any fungicides. not redistribute within the plant. In that case, they are called translaminar fungicides; trifloxystrobin is an example. Some Diseases in Home Lawns systemic fungicides move within the water-conducting tissue This publication is intended for professional turfgrass man - (xylem), which takes them upward in the transpiration stream; agers who use fungicides as part of an overall disease-control downward mobility within the plant is limited. These fungicides program as described above. Homeowners with diseased lawns are called xylem-mobile or acropetal systemics. Within this should obtain a copy of the University of Kentucky Cooperative group, some fungicides are moderately mobile within plants, Disease Management in the Home Lawn Extension publication such as certain DMI fungicides. Others are highly mobile and (PPFS-OR-T-11), available at your county Extension office or on move readily through the xylem. Examples of highly xylem- the Web at http://plantpathology.ca.uky.edu/files/ppfs-or-t-11. mobile systemics include thiophanate-methyl and mefanoxam. pdf. - A third type of systemic fungicide is the phloem-mobile sys PPFS-OR-T-11 describes cultural practices that usually can temic, which moves bidirectionally (from leaves to roots and alleviate infectious diseases in home lawns without the use of vice versa). Only one example of this type of systemic exists fungicides. Consider these limitations before using commercial among turfgrass fungicides: the phosphonates, which include fungicides: fosetyl-Al and the phosphites. y They are effective only against specific turfgrass diseases. Systemic fungicides sometimes can suppress the fungus after They must be applied at the right time to be effective. y it has infected the plant, whereas contact fungicides must be They have to be applied at the right rate to be safe and effective. y present on the plant’s surfaces before infection begins to be They often must be applied repeatedly. y effective. For these reasons, fungicide use by homeowners generally Preventive vs. Curative Use is discouraged. Certain fungicides labeled for disease control Fungicide labels usually provide a range of application rates may not be used in residential lawns; see product labels for such - and intervals. Fungicides can be used on a preventive basis (usu restrictions. - ally at lower rates and/or at longer intervals between applica Because of Food Quality Protection Act considerations, tions) when a disease outbreak has not yet occurred but when chlorothalonil, iprodione, and vinclozolin no longer are labeled weather favorable for disease is expected. Conversely, fungicides for use in home lawns. PCNB (pentachloronitrobenzene or may be used on a curative basis (often at higher rates and/or at quintozene) may also no longer be used on home lawns, as such, shorter intervals) after an outbreak has occurred and disease use was voluntarily revoked by manufacturers. pressure is high. Curative applications cannot cause sick tissues If applying “granular” fungicides to home lawns, here are some (yellow or brown leaves, rotted roots) to become healthy again. guidelines to help improve results: Curative applications can simply protect uninfected tissues and new growth and are only effective if the turf is actively growing. | Agriculture and Natural Resources | Family and Consumer Sciences | 4-H Youth Development | Community and Economic Development Cooperative Extension Service

2 Table 1. Fungicidal and selected biological materials for turf disease control. Risk of FRAC a b c d Fungicide Mobility Fungicide Group Some Product Names Resistance Code Benzothiadiazole L Daconil Action and Heritage Action premixes (see Table 2) Acibenzolar-S-methyl P1 PMS Heritage, Endow, ArmorTech ZOXY H XMS Q Azoxystrobin 11 I (= strobilurin) o L C EcoGuard NC Bacillus licheniformis Biocontrol agent NC Biocontrol agent L C Rhapsody Bacillus subtilis, strain QST 713 SDHI 7 XMS Emerald Boscalid M-H Phthalimide C Captan M4 NS Captan MA L-NS C Chloroneb 14 Terraneb SP, Anderson’s Fungicide V, Teremec M5 Chloronitrile NS C Daconil, Echo, Manicure, Chlorostar, Concorde SST, Chlorothalonil Pegasus L, Docket, ArmorTech CLT 21 QiI (Cyanoimidazole) M-H LP Segway Cyazofamid 14 Triadiazole C Koban, Terrazole Ethazole (etridiazole) NS DMI XMS Rubigan AS 3 M Fenarimol Pyridinamine, Oxidative Fluazinam 29 L C Secure, ArmorTech Rotator phosphorylation uncoupler 12 Phenylpyrrole L-M C Medallion, Nivales Fludioxonil 43 XMS M Fluopicolide Stellar (a premix with propamocarb) Benzamide 11 I (= strobilurin) H XMS Fame Fluoxastrobin Q o 7 SDHI M-H XMS Prostar Flutolanil 7 Fluxapyroxad M-H XMS Xzemplar SDHI Fosetyl-Al Phosphonate L PMS Chipco Signature, Signature Xtra Stressgard, Prodigy. 33 Aliette, ArmorTech ALT70, Viceroy 70DF Hydrogen dioxide NC Oxidizing agent L SC Zerotol Iprodione 2 LS Chipco 26019, Chipco 26GT, Andersons Fungicide X, Dicarboximide M-H Iprodione Pro, Raven, ArmorTech IP, Eclipse ETQ Isofetamid SDHI M-H XMS Kabuto 7 M3 EBDC NS C Fore, Manzate 200, Protect DF, Mancozeb, Dithane, Mancozeb Formec, Pentathlon, Koverall Mandestrobin 11 Q I (= strobilurin) H XMS Pinpoint o Mefenoxam Phenylamide H XMS Subdue Maxx, Quell, Mefenoxam, Fenox 4 Metalaxyl 4 Phenylamide H XMS Subdue 2E, Andersons Pythium Control, Apron seed treatment, Vireo Metconazole 3 DMI M XMS Tourney continued y Do not rely on fungicides alone for disease control. Avoid Fungicide Resistance using turfgrass varieties that are highly susceptible to com - Infectious fungi sometimes develop resistance to particular mon diseases, and use best cultural disease-management fungicides, especially when a product is used repeatedly without practices to reduce selection pressure on the fungus in order alternating with chemically unrelated fungicides and without to develop resistance. reducing disease pressure through cultural practices. When y Limit the number of times that at-risk fungicides are used fungicide resistance develops, use of that product or other during a growing season. Alternate at-risk fungicides with chemically similar products no longer controls the disease effec - products from different fungicide groups (= different modes tively. The risk of fungicide resistance is especially great for sev - of action / FRAC Codes). eral systemic fungicides. In Kentucky and New Jersey, fungicide When using an at-risk fungicide, tank-mix it with a fungicide y resistance has been confirmed in numerous instances for each of having another biochemical mode of action / target site to I the following diseases and fungicide groups: anthracnose to Q o reduce the risk of resistance buildup (but refer to fungicide (strobilurin) fungicides and to thiophanate-methyl, dollar spot labels before tank-mixing to ensure compatibility and to to thiophanate-methyl and/or DMI fungicides, gray leaf spot to avoid phytotoxicity). Q I (strobilurin) fungicides, and Pythium blight to phenylamide o Be sure to use proper nozzles and adequate carrier volume— y fungicides. In addition to these cases, examples reported from especially when tank-mixing a contact fungicide with an other states include resistance to benzimidazole fungicides in at-risk fungicide—to assure thorough coverage of all plant pink snow mold and powdery mildew, dicarboximide fungicides surfaces upon contact. I (strobilurin) fungicides in in dollar spot, and resistance to Q o y Use of below-label rates can speed selection of resistant strains Pythium blight. All systemic fungicides have some risk for the with certain types of fungicides. Thus, use tank-mixes at development of resistance, but certain groups of fungicides are below-label rates only for mixtures known to be synergistic. more at risk than others. Available contact fungicides essentially (Synergism means that disease control from the fungicide have no risk of resistance. The relative risk of resistance among mixture is better than expected—a greater than additive effect. the various fungicide families is noted in Table 1. An analogy is when one plus one equals three instead of two.) Several general strategies are recommended to minimize the FRAC codes (and the fungicide groups generally represented risk of fungicide resistance. Understand that these general prin - - by these codes) are found on all fungicide labels and are indi ciples can reduce but not eliminate risk. A fungicide-resistant cated for all fungicides listed in Table 1. This information allows pathogen population can still develop in swards where these turfgrass managers to rotate among (or tank-mix) fungicides principles are practiced. 2

3 Table 1. (continued) FRAC Risk of c a d b Fungicide Group Resistance Code Mobility Fungicide Some Product Names L XMS Civitas One Mineral oil NC Isoparaffin Myclobutanil 3 Eagle, Golden Eagle, ArmorTech Myclo XMS M DMI PCNB (pentachloronitro- Autilus (anthracnose only), Defend, PCNB, Penstar, C L-NS MA 14 benzene or quintozene) Terraclor, FFII, Engage, Turfcide, Revere Velista SDHI 7 Penthiopyrad XMS M-H Appear, Magellan, Biophos, Resyst, Alude, Vital Sign, PK- 33 Phosphonate L PMS Phosphite (salts of phosphorous acid) Plus, Fiata Stressgard LS Polyoxin 19 Polyoxin D zinc salt M Affirm, Endorse 28 Propamocarb Carbamate LS M Banol, Stellar (a premix with fluopicolide), ProPlant Banner Maxx, Propiconazole Pro, Spectator, Strider, Savvi XMS M DMI 3 Propiconazole 11 Q Insignia Intrinsic I (= strobilurin) H LS Pyraclostrobin o Regalia PTO Reynoutria sachalinensis NC Plant Extract L LS M Tebuconazole 3 DMI XMS Torque, Mirage Stressgard, Sipcam Clearscape ETQ, Offset, Skylark, ArmorTech TEB360 H XMS 3336 EG, Allban, Fungo, Anderson’s Systemic Fungicide, 1 Thiophanate-methyl MBC Systec 1998, Absorb TM, T-Storm, T-Bird, Tee-Off, ArmorTech TM, Cavalier Thiram M3 Dithiocarbamate NS C Spotrete, Thiram, Defiant XMS M DMI 3 Triadimefon Bayleton, Anderson’s Fungicide VII Bio-Trek, TurfShield PLUS, Turfmate C L Biocontrol agent NC Trichoderma harzianum Rifai T-22 plus Trichoderma virens G14 Compass 11 Q Trifloxystrobin I (= strobilurin) H LS o XMS Triticonazole 3 DMI Trinity, Triton M 2 M-H Dicarboximide Curalan, Touché, Vorlan Vinclozolin LS a NC = Not classified. FRAC codes indicate the biochemical target site of action, according to the Fungicide Resistance Action Committee. M3, M4, and M5 indicate multisite inhibitor, with no significant risk of resistance. b DMI = demethylation inhibitor; EBDC = ethylene bis-dithiocarbamate; MA = miscellaneous aromatic; MBC = methyl benzimidazole carbamate. c L = low; M = medium; H = high; NS = not significant. d C = contact (= protectant) fungicide; LS = locally systemic; XMS = xylem-mobile systemic; PMS = phloem-mobile systemic; SC = surface contact (no residue remains on leaf surface). having different biochemical modes of action / target sites. Sim - Evaluating Fungicide Efficacy ply choose among products that do not share the same FRAC Fungicides labeled for the control of specific turfgrass diseases code. FRAC codes for each fungicide are determined by the are listed under each disease discussed in this publication. The Fungicide Resistance Action Committee (FRAC), a worldwide relative effectiveness of these fungicides is also provided. For consortium of scientists representing fungicide manufacturers; each disease, labeled fungicides are given an efficacy rating from the codes are available in the tables below and at http://www. 1 to 4 based on relative effectiveness, where 4 is most efficacious. frac.info. Before tank-mixing pesticides, refer to product labels Efficacy ratings were assigned by reviewing the performance to ensure compatibility and to prevent phytotoxicity. of these fungicides in over 1,000 research reports published Plant Disease Management Reports, over a 38-year period in Prepackaged Fungicide Mixtures published by the American Phytopathological Society. These - Several products formulated for turf-disease control are pre reports are available on the Web at www.apsnet.org. Research packaged mixtures containing two or more active ingredients. Rutgers Turfgrass reports published over the past 35 years in the Some examples of prepackaged mixtures are listed in Table 2. (www.turf.rutgers.edu/research/reports/) were also Proceedings Mixtures generally provide some protection against fungicide used to calculate efficacy ratings. - resistance and typically provide a broader spectrum of activ Many reports from other sources, principally universities, ity against turfgrass diseases. Also, improved disease control also were evaluated. Experimental results were evaluated only (synergism) sometimes occurs with mixtures of fungicides. from validly conducted experiments with products used in a Prepackaged mixtures offer convenience and assurance against manner similar to label directions. For each disease, results - incompatibility; however, the application rate of an active in from numerous scientifically valid experiments were used in gredient in a prepackaged mixture might not be as high as the assigning ratings. rate when that same active ingredient is formulated alone. Thus, Be aware that disease-control products are marketed to a prepackaged mixture may not always perform as well as the turfgrass managers even though published information show - individual ingredients when formulated alone for all diseases ing effective control may be lacking from recognized scientific listed on the label. Efficacy ratings for individual ingredient and publications. Pesticide manufacturers are not required by law to prepackaged fungicide combination products are presented in demonstrate effective control of the disease listed on the label. the table accompanying each disease in this publication. Considering this, it seems wise to select from among disease- control products shown to be effective in published reports from scientifically valid evaluations. 3

4 Table 2. Prepackaged fungicide mixtures. Efficacy ratings in this publication are not a substitute for Some Product Names Active Ingredients instructions and restrictions provided on product labels. Always a azoxystrobin + acibenzolar-S-methyl Heritage Action use each pesticide product in a manner consistent with its label. azoxystrobin + chlorothalonil Renown Briskway azoxystrobin + difenoconazole Improving Spray Efficacy azoxystrobin + propiconazole Headway, Goliath WP, Contend B - For fungicides, use nozzles that provide excellent spray cover ArmorTech ZOXY-T, StrobeT azoxystrobin + tebuconazole benzovinduiflupyr + difenoconazole Contend A age. Use water-sensitive paper to evaluate the degree of spray a chlorothalonil + acibenzolar-S-methyl Daconil Action coverage obtained with different nozzles. Air-induction nozzles Instrata chlorothalonil + fludioxonil + produce large droplet sizes that help to control drift, but those propiconazole droplets shatter upon impact with plant surfaces, providing E-Pro ETQ chlorothalonil + iprodione chlorothalonil + iprodione + Enclave excellent spray coverage. thiophanate-methyl + tebuconazole For foliar diseases, contact fungicides sometimes provide Concert, Concert II chlorothalonil + propiconazole better performance when dew is removed or allowed to dry chlorothalonil + tebuconazole E-Scape ETQ Junction copper hydroxide + mancozeb before fungicide application, although this benefit has not been Stellar fluopicolide + propamocarb seen with systemic fungicides. It is thought that the high-water fluopyram + trifloxystrobin Exteris Stressgard volume sometimes present with dew causes some of the contact fluoxastrobin + chlorothalonil Fame C fungicide applied to run off onto the thatch or soil, reducing fluoxastrobin +myclobutanil Disarm M fluoxastrobin + tebuconazole Fame+T fungicide concentration on the leaf surface. For contacts, this 26/36, Dovetail, Twosome, iprodione + thiophanate-methyl loss of fungicide concentration would be expected to result in ArmorTech TMI reduced performance. In contrast, for root diseases, applying iprodione + trifloxystrobin Interface Stressgard fungicides (contacts or systemics) while dew is present probably Oreon PCNB + tebuconazole Vitalonil potassium phosphite + chlorothalonil enhances fungicide penetration into the root zone. pyraclostrobin + boscalid Honor Intrinsic pyraclostrobin + fluxapyroxad Lexicon Revisiting Fungicide Synergism pyraclostrobin + triticonazole Pillar - As mentioned previously, pesticide synergism is the phe thiophanate-methyl + chlorothalonil ConSyst, Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C nomenon whereby a combination of two pesticides gives better SysStar thiophanate-methyl + flutolanil control than would be expected by simply summing the control Armada, Tartan trifloxystrobin + triadimefon levels provided by the individual pesticides, analogous to 1+1=3. a Acibenzolar-S-methyl has been shown to slightly improve the control In cases of additivity, the combination works better than the of selected diseases compared to the same amount of chlorothalonil or azoxystrobin alone. individual pesticides but only as well as would be predicted by summing the pest control provided by the individual pesticides (1+1=2). And, of course, there is antagonism, which is when the on the turf ecosystem or the environment. Consider the combination of pesticides performs more poorly than would be possibility of nontarget effects when evaluating the need for expected by summing the pest control provided by the individ - fungicide applications. It should be noted that these nontarget ual pesticides (1+1=1). Careful and thorough testing is required effects are isolated events that are, except for phytotoxicity, usu - to demonstrate synergism, additivity, or antagonism, although ally less important than management of the disease for which funding for such tests is hard to come by. Consequently, few the fungicides were intended. However, they remind us of the research programs have done this kind of work. important responsibility to avoid unnecessary fungicide use. For many years, the only in-depth source of information on such possible interactions among fungicides in turf has been Phytotoxicity and Turf Growth Regulation Houston Couch’s excellent and comprehensive reference, “Dis - - Commercial fungicide products generally have been ex eases of Turfgrasses, Third Edition.” Recent well-conducted field haustively tested by the time they are marketed and rarely research in Georgia and Indiana indicates, however, that the cause injury to turfgrasses. In unusual circumstances, certain fungicide combinations reported in “Diseases of Turfgrasses” formulations of some active ingredients can cause temporary to be synergistic against dollar spot often performed disap - yellowing or browning, usually with no lasting effects on the pointingly. In this research, out of 108 separate evaluations turf. An effort has been made to note these possibilities in this (fungicide mixture x assessment date) of dollar spot, only three publication. were synergistic. As a class, the DMI fungicides can exhibit growth-regulating - Recent research does not negate the value of mixing fun - effects on turfgrass through inhibition of gibberellic acid syn gicides. Fungicides in mixtures usually do act additively, and thesis. These fungicides sometimes produce a desirable darker mixing fungicides can help to reduce the risk of fungicide - green color on turfgrass. However, undesirable effects some resistance. But the latest research raises questions as to the times include a coarser appearance through a widening of leaf consistency of fungicide synergism (1+1=3) for disease control blades, color changes (such as yellowing, a bluish appearance, under field conditions. or bronzing or browning of turf ), and reduced growth rate. Research clearly has shown that putting-green turf exhibiting Nontarget Effects of Fungicides growth-regulating effects of DMI fungicides can suffer signifi - Well-informed turf managers always recognize that fungi - cantly greater infestations of algae in the summer as a result cides and other pesticides can have unexpected consequences of decreased turf density. Growth-regulating effects of DMI 4

5 fungicides generally are associated with high use rates and/or re - turf areas that receive intensive pesticide applications can, under peated applications, particularly on turf under stress from high - certain circumstances, be sources of environmental contami nation by runoff. As an example, the fungicide chlorothalonil temperatures or drought. All DMI fungicides have the potential (the active ingredient in Daconil and many other products) is to cause injury under selected circumstances, especially when highly toxic to fish, aquatic invertebrates, mollusks, and shrimp. the turf is under stress. Therefore, avoid repeated application of Because of these facts and the heavy use of this fungicide on DMI fungicides at high rates without rotation to other modes turfgrass, the U.S. Environmental Protection Agency has im - of action when turf is under heat stress, water stress, or some other acute stress. Products containing mineral oil or PCNB posed restrictions on chlorothalonil use in turfgrass and other may also cause phytotoxicity on cool-season turfgrasses under crops to reduce the risk of disruption to aquatic ecosystems. Be these circumstances and thus are typically only recommended sure to heed use restrictions on the chlorothalonil label as to the maximum rate allowable and the number of applications for use during cool weather in the spring and autumn. that can be made each season. Widespread abuse of restrictions - During hot summer months, use DMI fungicides on put on chlorothalonil could put the registration of this and other ting greens at low rates, and rotate them with other fungicides fungicides at risk. to reduce overall DMI use. Care should be taken when using Be aware of potential risks to the quality of surface waters both DMI fungicides and certain plant growth regulators whenever pesticides are applied. To reduce the risk of water (PGRs) on putting greens, especially paclobutrazol (Trimmit) and flurprimidol (Cutless). The possible additive effect of their - contamination in runoff, consider the following recommenda tions: - similar chemistries can cause significant turf growth suppres sion and discoloration. This damage is most evident in bentgrass y Apply pesticides to turf only; avoid application on non-turf surfaces (driveways, cart paths, etc.). putting greens that have many segregated colonies of bentgrass y and/or annual bluegrass genotypes. Use care when applying pesticides to saturated or frozen soil or prior to a forecast of heavy rainfall. Thatch Accumulation If irrigating following pesticide application, be sure not to apply y Several fungicides (thiophanate-methyl, iprodione, man - irrigation at a rate that exceeds the infiltration rate of the soil. cozeb, and thiram) have been found to enhance thatch accu - y Use care when applying pesticides during the early phase of a mulation in turf under intensive management. Benzimidazole grow-in (new seeding) because the incomplete soil coverage fungicides are toxic to earthworms, and, because earthworms by vegetation permits greater amounts of runoff. - play an important role in thatch decomposition, benzimid y Maintain unsprayed vegetation as filter strips along streams, azole fungicides can encourage thatch to accumulate. All of ponds, lakes, and sinkholes. Turf can range from being mowed these fungicides can have an important place in a turf disease- - at 3 inches or higher to unmowed but attractive native veg management program, but one should avoid exclusive use of etation and wildflowers. In addition to serving as filter strips, these products at high rates. certain types of vegetation can also provide wildlife habitat. y Do not apply pesticides in wind, and use nozzles designed to Disease Enhancement or Resurgence reduce spray drift to nontarget areas. Many fungicides are selectively toxic to certain groups of fungi. They often do an excellent job of controlling the target Unanticipated Detrimental Effects of Pesticides - fungal disease, but in some instances can cause increased pres In the past, an accepted way to evaluate the safety of chemi - sure from another fungal disease normally not controlled by the cals was to feed them to laboratory animals at high doses and product. One important example of this disease enhancement monitor for negative consequences such as poisoning, birth in Kentucky is the enhancement of summer patch by applica - defects, cancer, and so on. While these studies can produce tions of chlorothalonil. Dollar spot also can be enhanced by important findings, it turns out they may not identify all the azoxystrobin or flutolanil. The precise mechanisms of disease - harmful effects of chemicals. In recent years, scientists have dis enhancement often are not well understood for any given case. covered that even low doses of certain chemicals over prolonged However, possible mechanisms include suppression of antago - periods might have adverse effects by disrupting the endocrine nistic microorganisms naturally present in the turf ecosystem system—the hormonal system of the body. Such “endocrine and enhanced physiological stress on turf already under water disruptors” can evidently cause a permanent disruption in an - stress from a root disease. Field research in Kentucky and else animal’s endocrine system, even long after the exposure to the where has documented instances of disease resurgence follow - chemical and even at low doses to which humans are likely to ing fungicide application. This means that the target disease was be exposed. This endocrine system disruption can happen when controlled during the period of fungicide effectiveness but then the exposure occurs at critical times in the body’s development, became more severe than in untreated plots after the fungicide including before birth. Endocrine disruptors can produce these was metabolized or weathered away. - alterations by inducing epigenetic changes (altered gene expres sion), thus affecting the genetic programming of the animal’s Pesticide Contamination of Surface Water by Runoff cells. Certain pesticides and other synthetic chemicals have Usually, the amounts of pesticides applied to turf that move been demonstrated to be endocrine disruptors. While there are off-target in runoff are low to insignificant. This is because ma - merits to the appropriate pesticide use for management of turf ture turfgrass swards provide a dense perennial vegetation cover diseases, the studies of endocrine disruptors serve once again that favors water retention and chemical adsorption. However, as a reminder that synthetic chemicals sometimes pose risks 5

6 that we don’t understand or even know about. Thus, to reduce ing mowing frequency and increasing rolling frequency may the potential for detrimental effects of pesticides, always do the also be useful practices during stress periods. According to research at Rutgers University, Michigan State University, following: and Cornell University, a potential loss of quality and green Minimize unnecessary exposure to pesticides by using them y only as part of a comprehensive IPM / Best Management speed due to reduced mowing frequency or raising the height of cut can be offset by rolling with lightweight rolling (see program. Consider using reduced-risk pesticides when they are available. y below). Use mowers with smooth instead of grooved rollers y Always use personal protective equipment when applying any and with sharp reels. Skip mowing every third or fourth day or even more frequently if the green is so stressed that it is pesticide, no matter how safe you may think the product is. not growing rapidly. Minimize cleanup passes, mowing them Pesticide Breakdown at High pH even less frequently. Use lightweight walk-behind mowers on Pesticides are generally most stable when the pH in the stressed greens, if possible, especially on the cleanup pass. spray tank ranges from 4 to 6. Certain pesticides can chemi - Once stressful conditions slow turf growth, disengage or cally decompose quickly above pH 7.0; this phenomenon is remove grooming devices such as brushes and combs. called alkaline hydrolysis. If a pesticide is subject to alkaline y Under stressful conditions, slower green speeds resulting from hydrolysis, leaving the product in a spray tank with high-pH reduced mowing frequency or increasing the height of cut can water for several hours or overnight can result in substantial or be offset by rolling greens with lightweight rollers (vibratory complete loss of pesticide efficacy. In the most extreme case, the or sidewinder) up to three times/week. This practice can help insecticide trichlorfon in Dylox is known to have a half-life of maintain green speed and reduce the severity of stress related just a few minutes at pH 8.0 but a half-life of 3.7 days at pH 6.0. diseases such as anthracnose and dollar spot by allowing the Alkaline hydrolysis is a concern with the fungicides polyoxin D turf to increase leaf mass and therefore its rate of photosyn - and thiophanate-methyl; other fungicides listed in Table 1, such thesis. For best results, a rolling program should be initiated as chlorothalonil, also can be subject to alkaline hydrolysis at or by May 1 to give the turfgrass time to adapt to the treatment - above pH 8.0. Check the pH of the water you use to mix pesti before the heat of summer. cides, and read the manufacturer’s material safety data sheets y Take care to avoid root-zone saturation. Proper irrigation or check with technical representatives to see if the products and drainage will improve soil oxygen levels and reduce heat you are using are subject to alkaline hydrolysis. If so, consider conduction into the root zone. It will also speed cooling of the adding a buffering agent to the spray tank, especially in cases root zone at night. Under high temperatures, overwatering is where the entire contents of the tankful will not be completely just as detrimental as a water deficit because it prevents roots sprayed immediately. from absorbing oxygen. When irrigation is needed, apply water by hand to avoid over-irrigating, irrigating only collars and Formulation elevated areas of the green if possible. Hand-irrigate known Several fungicidal products are available in more than one dry spots prior to wilting by using moisture sensing sensors formulation. For contact fungicides, a sprayable formulation (e.g., TDR probes) to detect dry soil conditions before drought (wettable powder, flowable, dry flowable, water-dispersible stress occurs. Consider using a wetting agent when hand- granule, micro-emulsion, or emulsifiable concentrate) usually watering known dry spots. If roots are shallow, irrigate only - provides better control of foliar diseases than a granular for to the depth of the roots. However, if roots are still healthy mulation. Sprayable formulations can be superior to granular at the onset of hot weather, watering deeply and infrequently formulations, even for systemics that are not highly mobile in (rather than lightly and frequently) will promote adequate soil plant tissues, such as certain DMI fungicides. Spray equipment oxygen and result in a healthier turf with better carbohydrate allows more thorough coverage of plant surfaces than does a status and root health during the most stressful weather. granular spreader. More thorough coverage can result in better Minimize leaf wetness caused by dew. Irrigation applied during y control of fungi that infect foliage. If granular fungicides are the evening hours when dew is present around sunrise can being used for foliar disease control, their effectiveness can be reduce the duration of leaf wetness periods. Also, mowing improved by applying them to wet leaves. Do not mow, and do or poling during early morning hours can be very beneficial not collect clippings immediately after application. by removing dew and guttation water which can encourage If fungicide sprays are being applied to control a root disease, infection. it is often advisable to lightly irrigate before the fungicide dries Minimize mowing when the turf is soggy, since the equipment y to move it into the root zone. Likewise, if granulars are being will sink into the turf, potentially scalping it. This practice is applied to control root diseases, apply to dry turf and irrigate especially important where thatch accumulation has become after application. excessive, and in native (e.g., loamy) soils where traffic imposed during soggy conditions will greatly increase compaction. Reducing Summertime Stress on Putting Greens y For improved root-zone aeration and cooling during hot Since numerous infectious agents can be more damaging weather, “vent” greens by creating small, non-disruptive holes when putting-green turf is stressed, the following agronomic that allow gas exchange, encourage evaporation of excess soil - practices can be an important component of disease manage moisture, and keep the surface from sealing. Venting can be ment in summertime. accomplished with needle tines, spiking, or other means. Raise mowing height if possible. An increase of as little as y Such non-disruptive cultivation should be done at three-week - 0.031 inch to 0.062 inch often can help reduce stress. Reduc 6

7 particularly during heat stress. Avoid applications of pesticides intervals beginning in early summer to maintain oxygen in the root zone, thus reducing the detrimental impact of a when the temperature exceeds 85 ° F (29 ° C) unless a serious disease or pest problem (such as Pythium blight) threatens sudden onset of hot weather. During the heat of summer, perform these operations during evening hours to reduce the health of the turf. stress on the turf. Minimize use of herbicides during heat stress periods. Many y y On hot days, syringe during the afternoon to reduce heat herbicides, especially some oil-based and ester-based formu - stress, applying water to the foliage only. Instead of using the lations, can cause turfgrass injury when applied during high irrigation system, use a nozzle that produces a fine mist so as temperatures. Volatilization of pesticides is also greater at to avoid applying water to the root zone if the soil is nearly higher temperatures. saturated. Systems that force air movement through the root In cases where roots have deteriorated (brown and/or short y zone of the green can improve turf health during summer by roots), whether from infectious disease or noninfectious stress, - removing CO raise height of cut by 0.0625 inches or more, and possibly re and excess water from the root zone (thereby 2 move grooved rollers to reduce stress. Since such turf has an increasing oxygen content) as well as possibly lowering soil extremely limited root system, irrigate lightly and frequently temperatures. These systems should be monitored carefully to provide sufficient water for growth and to reduce wilting. to avoid removing too much water and increasing localized Hand-watering affected areas is advisable if possible so that dry spot and drought stress. y Use foliar applications of soluble nitrogen at rates of 0.125- - the unaffected portions of the green do not become overwa 0.25 lb N/1,000 sq ft every 10-14 days. Avoid fertilization rates tered. Lightly spiking the greens will help improve aeration exceeding 0.25 lb of quick-release N/1,000 sq ft in a single and surface sealing—usually caused by algae or moss. But consider light spiking only if the daily temperatures are not application; too much fertilization can encourage excessive growth of disease-susceptible foliage and diminish root re above 90 F. Since roots are damaged and will take up nutrients ° - in the soil very poorly, fertilize every week or two with a foliar serves. For a darker green color, apply 2 oz/1,000 sq ft of iron soluble-nitrogen product that provides from 0.125-0.25 lb of sulfate or 3 oz/1,000 sq ft of iron chelate. Iron sulfate has also actual N/1,000 sq ft. been shown to reduce the incidence of dollar spot and pink y snow mold. Some nitrogen is necessary for turf growth and During stressful periods, minimize foot traffic to the extent stress tolerance, so maintain fertility even when the green is possible. Use ropes and other barriers to control and disperse under stress. However, avoid high fertility rates in summer, as foot traffic onto greens. Change hole cup locations frequently, this can enhance the activity of diseases such as brown patch and slow down green speed to open up more of the green to and Pythium blight and may have other negative physiological pin placement. Reschedule events to periods more favorable to grass growth. effects on cool-season turfgrasses. Applications of the turf growth regulator trinexapac-ethyl y Continue topdressing but at a light rate. When topdressing y at other times of the year, use sand with some degree of an - (Primo Maxx) can help prepare turfgrass for stress periods gularity to enhance stability under foot traffic. Verticutting - by redirecting carbohydrates to storage instead of leaf expan should be curtailed during periods of heat stress, and topdress sion. However, multiple applications at one- to three-week intervals are generally required for increased stress tolerance. no more often than every two to three weeks during normal summer weather. This practice will also improve the quality and vigor of annual y Rotate hole (cup) locations frequently to minimize traffic Poa annua bluegrass ( ). i nju r y. Miscellaneous Notes y Where air circulation and cooling are inadequate, selectively Commercial pigment products may improve the aesthetic prune or remove trees and underbrush or install fans. Fans appearance of turf. However, to our knowledge, no reports exist should be monitored carefully to avoid excessive drying and of enhanced disease control activity from such products in field increasing localized dry spot. trials. - Use fungicides judiciously, since several contacts and system y ics have the potential for phytotoxicity or growth regulation, 7

8 1. Algae (not a true disease) 1. Algae Various terrestrial blue-green and green Pathogen: a algae Principal hosts: Creeping bentgrass, annual bluegrass FRAC Efficacy* Interval Code (days) Some Trade Names : Fungicide May-October Season: 3.5 M5 chlorothalonil: Daconil Ultrex, Manicure, Concorde SST, 7-14 Chlorostar, Echo - Algae on greens may indicate overwatering, poor drain b Secure 29 14 fluazinam: L age, and/or shady conditions. To reduce algal scum on the 2 fluxapyroxad: Xzemplar 7 14-28 soil surface, decrease shade and increase air circulation 7 hydrogen dioxide: Zerotol NC 1 around greens. Allow the surfaces to dry completely be - mancozeb: 3 M3 7-14 Fore, Manzate 200, Protect T/O, Mancozeb, Dithane, Pentathlon tween irrigation events. Avoid irrigation in late afternoon 7-14 1 NC quaternary ammonium compounds: Algaen-X, Consan or in evening prior to midnight. Spike greens and topdress Triple Action 20, Quickstop every two to four weeks to promote surface drying. Allevi - Trinity, Triton 3 2 14-28 triticonazole: ate compaction. Control diseases and other stresses that Combination Products 11 + M5 Renown azoxystrobin + chlorothalonil: 10-14 L lead to an open turfgrass canopy. Use fungicides only in chlorothalonil + acibenzolar-S-methyl: M5 + P1 3.5 7-14 Daconil Action conjunction with good water management. Preventive chlorothalonil + propiconazole: M5 + 3 4 Concert, Concert II 7-28 applications are superior to curative applications. Fol - copper hydroxide + mancozeb: 7-14 Junction M1 + M3 4 low label recommendations regarding gallonage (carrier 11 + M5 L fluoxastrobin + chlorothalonil: Fame C 7-14 L 33 + M5 potassium phosphite + chlorothalonil: Vitalonil 7-14 volume); addition of surfactants is not recommended. a NC = Not classified. DMI fungicides can sometimes enhance algal infestation b Tank-mix with another fungicide from among those listed on label for enhanced through growth regulation that causes an opening of the algae control. turf canopy. This is most likely when DMI fungicides are include high temperatures, low pH of spray solution (as happens applied at high rates and/or short intervals during periods with when the product is tank-mixed with certain products like ° C), especially when other stresses ° F (29 temperatures above 85 Chipco Signature or products containing thiophanate-methyl), - are present. In one putting-green experiment, an organic nitro or tank-mixing with herbicides. Also, repeated use of copper - gen source favored algal development, whereas inorganic nitro hydroxide at high rates will lead to copper buildup in the soil, gen did not. Copper hydroxide may suppress algal formation but which creates a potential risk of phytotoxicity if the soil pH has the potential to cause phytotoxicity (yellowing or necrosis becomes unusually low. Potassium salts of fatty acids may be Poa species. of foliage tips) on cool-season grasses, especially on C). phytotoxic above 80 ° F (27 ° Conditions that enhance phytotoxicity from copper hydroxide During periods of high temperature and humidity y 2. Anthracnose It should also be noted that active anthracnose has been found Pathogen: Colletotrichum cereale (Colletotrichum graminicola) occasionally under snow cover in late winter in Pennsylvania. ta [ kahlay- Pronunciation: ah -lay ] trickum ] [ siri- During these high-risk periods, minimize practices that cause -ola ] nick trickum ] [ gramma- ta [ kahlay- stress to the plant (discussed below). Principal hosts: Annual bluegrass, creeping bentgrass Basal anthracnose on annual bluegrass appears to be favored Season: June-September on creeping bentgrass, April- November in annual bluegrass by slow percolation of soil water (e.g., overwatering) as well as by excessively dry conditions. Excessive soil wetness can be On creeping bentgrass, the disease anthracnose is associated particularly conducive to disease; therefore, improve drainage with warm weather. On bentgrass sites with a history of the and avoid overwatering. High organic-matter content in the disease, begin fungicide applications in mid-May, continuing root zone of a sand-based green can hold excessive moisture until the end of August. On greens with the basal rot phase of and may favor infection. If this condition exists, apply one of the disease, use walk-behind mowers and raise the height of two treatments in spring and autumn: aerify with 0.25-inch - cut. Irrigate greens as needed to avoid drought stress. If sow to 0.50-inch tines on close spacing (1.25 inches to 1.5 inches) ing new greens, consider adapted creeping bentgrass cultivars just deeply enough to penetrate the organic layer, then backfill with moderate resistance to anthracnose (see http://www.ntep. holes with sand; or if heavy organic matter is in the top inch, org). Avoid the most susceptible cultivars, such as Providence, deep verticutting will remove organic matter more effectively Pennlinks II, Penncross, Seaside II, and Brighton. than aerification but will require longer recovery times, so this On annual bluegrass greens, basal anthracnose can develop practice should be used only if good growing conditions prevail. under a wider range of temperatures than in creeping bentgrass. Also, avoid allowing the turf to wilt, particularly from midday There are four peak periods of anthracnose development: to late afternoon, as that may enhance susceptibility. Irrigation During cool/moist periods in early spring and even through y that achieves 80% replacement of daily evapotranspiration winter if conditions are mild and wet (ET) is ideal from the standpoint of anthracnose management, During periods of extended overcast conditions in late spring y based on studies at Rutgers University. Shady conditions can Following peak periods of flowering in early summer, y * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most experiments; = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 8

9 2. Anthracnose (continued) 2. Anthracnose a a Efficacy* FRAC FRAC Efficacy* Interval Interval Code Code (days) (days) Some Trade Names Fungicide: Combination Products (continued) b 7-14 chlorothalonil + acibenzolar-S-methyl: 3 M5 + P1 Daconil azoxystrobin: 11 Heritage 14-28 1/3 Action 3-14 NC Bacillus licheniformis: 1 EcoGuard L chlorothalonil + fludioxonil + propiconazole: 14-28 M5 + 12 Bacillus subtilis, strain QST 713: 7-10 NC 1.5 Rhapsody Instrata + 3 7-14 3 M5 Daconil Ultrex, Manicure, chlorothalonil: chlorothalonil + iprodione: M5 + 2 L E-Pro ETQ, Chipco 14 Concorde SST, Chlorostar, Echo, Pegasus L 26GT + Daconil Ultrex fenarimol: Rubigan 3 2 30 chlorothalonil + iprodione + thiophanate- M5 + 2 + 3.5 14-28 Secure fluazinam: 1.5 14 29 methyl + tebuconazole: 1 + 3 Enclave 3 14 fludioxonil: Medallion 12 chlorothalonil + propiconazole: Concert, 3 M5 + 3 14-28 b 14-28 11 Fame fluoxastrobin: 1/3 Concert II c 14 Chipco Signature, Signature Xtra fosetyl-Al: 33 NA E-Scape ETQ M5 + 3 L 28 chlorothalonil + tebuconazole: Stressgard ConSyst, chlorothalonil + thiophanate-methyl: 2.5 M5 + 1 14 L Zerotol NC hydrogen dioxide: 7 Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C c 2 Chipco 26 GT iprodione: Unspecified NA 14 fosetyl-Al + chlorothalonil: on-site tank-mix of 33 + M5 3.5 3 Tourney 3 14-21 metconazole: labeled solo products. d mineral oil: 7-14 NC Civitas 3 Exteris Stressgard 7+11 L 14-28 fluopyram + trifloxystrobin: Eagle myclobutanil: 3 2 14-21 3 fluoxastrobin + chlorothalonil: Fame C 11 + M5 14-28 d 7-10 Autilus 14 PCNB: 3 11 + 3 3 14-28 Disarm M fluoxastrobin + myclobutanil: e 7 penthiopyrad: 14 Velista 3 3 11 + 3 fluoxastrobin + tebuconazole: Fame+T 21-28 2 to phosphite (salts of phosphorous acid): Alude, 33 14 iprodione + thiophanate-methyl: 26/36, 2 + 1 L 14-21 f 3 Appear, Magellan, Biophos, Resyst, Vital Sign, Dovetail, Twosome, ArmorTech TMI PK-Plus iprodione + trifloxystrobin: Interface Stressgard L 14-28 2 + 11 Affirm 19 3 7-14 polyoxin D: g Oreon 14+3 14-21 PCNB + tebuconazole: 3.5 Banner, Spectator, Savvi 3 14-28 2.5 propiconazole: L 14 potassium phosphite + chlorothalonil: 33 + M5 b 11 Insignia Intrinsic pyraclostrobin: 14-28 1/3 Vitalonil NC 7-14 Reynoutria sachalinensis: 1 Regalia PTO 14-28 3 11 + 7 Lexicon pyraclostrobin + fluxapyroxad: Torque, Mirage Stressgard, 3 14-28 tebuconazole: 3 11 + 3 14-28 pyraclostrobin + triticonazole: L Pillar Sipcam Clearscape ETQ, Offset, ArmorTech thiophanate-methyl + flutolanil: 1 + 7 14-30 SysStar L TEB360 11 + 3 Armada, Tartan 14-28 trifloxystrobin + triadimefon: 2 b 3336 EG, Fungo, Systec thiophanate-methyl: 1 10-14 1/2 a NC = Not classified. 1998, Cavalier, T-Storm b Lower efficacy rating applies when isolates of C. cereale resistant to azoxys - 14-45 1.5 3 Bayleton, Andersons Fungicide VII triadimefon: I fungicides) and/or thiophanate methyl are present. trobin (and related Q o b trifloxystrobin: Compass 11 14-21 1/3 Resistance is very common in numerous locations throughout the U.S. c triticonazole: Trinity, Triton 3 14-28 3 NA = not applicable. The Chipco 26GT and Chipco Signature labels require tank-mixing with selected fungicides for anthracnose control; variable con - Combination Products trol can be expected from each of these products when sprayed alone. d azoxystrobin + acibenzolar-S-methyl: 11 + P1 L 14-28 Heritage To reduce the potential for phytotoxicity, do not apply during hot weather Action - (> 90°F) or periods of severe environmental stress, and do not tank-mix Ci azoxystrobin + chlorothalonil: Renown 11 + M5 2.5 7-21 vitas with PCNB or combine with chlorothalonil, DMI fungicides, or iron- containing products when temperatures and humidity are high. azoxystrobin + difenoconazole: 11 + 3 L 14 Briskway e More effective when used preventively as compared to curatively. Headway, 14-28 azoxystrobin + propiconazole: 11 + 3 3 f More effective for controlling anthracnose on Poa annua than on creeping Goliath bentgrass; should be tank-mixed with selected fungicides to enhance ef - ArmorTech L 11 + 3 azoxystrobin + tebuconazole: 14-21 ficacy and longevity of control. ZOXY-T, StrobeT g Do not apply to cool-season turf at daytime temperatures of 85°F or higher. b 14-28 7 + 11 Honor Intrinsic boscalid + pyraclostrobin: 1/3 - Combine Autilus and Oreon with a pigment to mask chlorosis that may oc cur at high label rate. After application, immediately irrigate with 1/4 inch water. also enhance susceptibility. As conditions warrant, begin speed can enhance disease severity. Studies in Connecticut and preventive fungicide applications by mid-April and continue Pennsylvania suggest that a foliar nitrogen content of between 3.6 and 5% in annual bluegrass reduces susceptibility signifi applications into mid-October. Under severe disease pressure, - cantly. Total nitrogen fertilization should be approximately 3-4 research shows that biweekly fungicide applications may be needed from early April through mid-November. If tempera lb N/1,000 sq ft per year, with more applied in the spring than in - tures are above normal in December through February, begin a the autumn. Potassium deficiency in the soil and mat layer has preventive program on annual bluegrass in early to mid-March, been associated with increased disease development; therefore, apply potassium to maintain moderate to high levels in the especially if conditions in early spring are wet. Some studies -1 show enhanced control of basal anthracnose when using DMI ) and tissue (> 2.0% K in clippings). soil/mat layer (> 100 lb K ac fungicides applied in 5 gal of water/1,000 sq ft, as compared to Soluble-K applications should be made bi-weekly at a 1:1 or 2:1 N:K molar adjusted-ratio to reduce anthracnose severity. lower carrier volumes. If the disease has been active, avoid use Acidic conditions have been found to enhance anthracnose, so of turf growth regulators that might delay recovery. keep soil pH between 5.8 and 6.0. Raise the mowing height if For both annual bluegrass and creeping bentgrass, be sure to provide sufficient soluble nitrogen to maintain a moderate possible, since studies have shown substantially increased basal growth rate through the summer (foliar applications of ap - rot at lower mowing heights; an increase of 0.020 inch can be proximately 0.10-0.25 lb soluble N/1,000 sq ft applied every 7-14 significant. Indeed, it may not be possible to completely control the disease with fungicides on annual bluegrass greens when days), as low levels of nitrogen used to promote increased ball * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most 1 = no N = control is inconsistent between experiments but performs well in some instances; experiments; = fair to good control in most experiments; 2 = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 9

10 been shown to control anthracnose preventively in most tests mowed at or below 0.125 inch. Lightweight vibratory rolling on creeping bentgrass and annual bluegrass putting greens (vibratory or sidewinder) can help maintain acceptable green during summertime. If curative applications are necessary, speed without increasing, and in some cases slightly decreasing, they should include chlorothalonil tank-mixed with a systemic disease severity. for best results; avoid use of chlorothalonil alone, since in one Verticutting to a depth that could cause “severe wounding” test this fungicide when used alone reduced summertime root of crowns and stolons (0.2 inch) has been shown to enhance - length in a creeping bentgrass putting green. anthracnose damage. When disease pressure is high; how The fungicide flutolanil and the pre-emergent herbicides ever, grooming that affects only leaf tissue has been shown to dithiopyr (Dimension) and bensulide (Betasan) have been slightly reduce anthracnose severity. Thus, verticutting or other cultivation practices (e.g., aerification, scarification, grooming) shown to enhance damage from anthracnose, as has repeated should be done carefully to avoid extensive turf damage when application of iprodione and vinclozolin used alone. When using anthracnose is present, and fungicides should be applied before thiophanate-methyl, check the pH of the water used to prepare spray solutions; if the pH is high, include a buffering agent to utilizing any cultivation practice when the disease is active. 2 bring the pH to between 6.0 and 7.0 to avoid alkaline hydrolysis. Topdressing in the spring at 400 to 800 lb per 1,000-ft is more effective than fall applications at reducing anthracnose sever - Repeated applications of trinexapac ethyl (Primo) even at 2 every high rates and short intervals have not increased and have in ity. Light, frequent topdressing (up to 200 lb per 1,000 ft two-weeks) throughout the summer has consistently reduced some cases reduced anthracnose severity. This is especially - - true when applied at seven-day intervals, possibly by improv disease severity compared to non-topdressed plots. This im ing turf tolerance to low mowing and enhancing plant health. provement seems related to improving surface characteristics of Similarly, application of mef luidide (Embark) or ethephon the green and helping to protect the growing point from mow - ing, allowing for closer mowing without stressing/weakening (Proxy) + trinexapac ethyl in the spring to suppress annual bluegrass seedheads will not increase disease and sometimes the crown. Particle shape of the sand (subangular vs. round) and has resulted in a reduction of anthracnose severity. In almost different sand incorporation techniques (brushing, dragging, all tests of the growth regulator mefluidide (Embark) applied rolling, or irrigation) do not appear to influence anthracnose for seedhead suppression, no effect on anthracnose severity development, so select the method that best incorporates sand into the canopy to minimize turf injury and wear on mowing has been observed. However, following a program of applying equipment. Minimize mowing when the turf is soggy, since mefluidide or ethephon in March or April at label rates with subsequent applications of trinexapac-ethyl (Primo Maxx 1ME) the equipment will sink into the turf, potentially scalping it. 2 Use walk-behind mowers, and reduce mowing frequency if the at 0.1 to 0.2 fl oz/1,000 ft every 7 to 14 days on annual bluegrass - putting greens should provide excellent turf quality and may green is growing slowly. Rolling greens with lightweight roll ers (vibratory or sidewinder) three times/week, coupled with reduce anthracnose, possibly because of the combination of several stress-reducing physiological effects. regular topdressing, can reduce anthracnose pressure. For best I fungicides have per - results, a rolling program should be initiated by May 1 to give Although azoxystrobin and other Q o formed well in early research trials, the emergence of resistant the turfgrass time to adapt to the treatment before the heat of summer. Monitor soil water content to identify the location of strains is a concern in Kentucky and nationwide. High levels of dry spots, and irrigate to avoid wilting, particularly between resistance to Q I fungicides (FRAC Code 11) and to thiophan - o ate-methyl (FRAC Code 1) have been documented in anthrac - mid-day and late afternoon. Hand water whenever possible. Typically, preventive spray programs have been much more nose isolates collected from many locations. Because of this effective than curative programs against this disease. The resistance, superintendents should not rely on these fungicide families for anthracnose control; instead, chlorothalonil, fosetyl- combination of Civitas + Harmonizer with another moderately effective anthracnose fungicide sometimes results in improved Al, fludioxonil, DMIs, penthiopyrad, and polyoxin D, mineral oil fungicidal efficacy. A good guideline is to begin a preventive (Civitas), and PCNB will be the best choices for many locations. program approximately one month before the typical onset of Note that these materials are best used as preventive rather than - symptoms at the site. In numerous studies, preventive applica curative applications and that mineral oil and PCNB may cause C)) or periods of tions of fungicide mixtures have provided better control than phytotoxicity during hot weather (> 90 ° F, 3 2 ° - severe environmental stress. For courses where Q I fungicides the single fungicide products used alone. Preventive applica o - tions of reduced-rate tank-mixes of a DMI fungicide and chlo and/or benzimidazole are still effective against anthracnose, rothalonil at two-week intervals have provided excellent control avoid sequential applications of either fungicide family in order in a number of experiments on creeping bentgrass greens. Avoid to reduce the risk of fungicide resistance. For the same reason, high rates of DMI fungicides on putting greens during summer - it is advisable when using these fungicides for anthracnose con because of the possibility of undesirable growth-regulator ef - trol to tank-mix them with a contact fungicide. For sites with I fungicides and thiophanate-methyl, multiple resistance to Q - fects. When using DMI fungicides alone for anthracnose con o the following are examples of combinations that can be used, trol, apply in 5 gal of water/1,000 sq ft. For all other fungicides, a minimum spray volume of 2 gal/1,000 sq ft coupled with all at 14-day intervals (products with identical active ingredients may be substituted at equivalent active ingredient rates): nozzles providing excellent one-pass coverage is recommended. Chipco Signature 80WDG + Daconil Ultrex 82.5WDG (4.0 y Tank-mixes of fosetyl-Al + iprodione or chlorothalonil have also oz + 3.2 oz/1,000 sq ft) * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most 1 = no N = control is inconsistent between experiments but performs well in some instances; experiments; = fair to good control in most experiments; 2 = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 10

11 surfactant has sometimes Repeated applications of DewCure ® Chipco Signature 80WDG + Fore Rainshield NT 80WP (4.0 y caused mild phytotoxicity when used alone and substantial oz + 8.0 oz/1,000 sq ft) phytotoxicity when used in combination with chlorothalonil. In Banner Maxx 1.3MEC + Daconil Ultrex 82.5WDG (1.0 fl oz y + 3.2 oz/1,000 sq ft) several experiments, the combination of Civitas + Harmonizer Medallion 50WP + Daconil Ultrex 82.5WDG + Banner Maxx caused phytotoxicity ranging from mild to severe. Turfgrass y - that is under biotic or abiotic stress is more prone to phyto 1.3ME (0.25 oz + 3.2 oz + 1.0 fl oz/1,000 sq ft, respectively). toxicity from this combination. Similarly, products containing Reports of quantitative resistance (reduced sensitivity) to PCNB should not be applied to cool-season turf when daytime DMI fungicides (FRAC Code 3) have emerged recently as well, ° temperatures exceed 85 C). Phytotoxicity to creeping ° F (29 although to our knowledge these resistant strains are not yet bentgrass managed as a putting green was observed in one test widespread. Diagnosis of anthracnose on turf (any species) at with Instrata 3.6SC and with a combination of Tourney 50WG - fairway height or higher often suggests involvement of a pre + Primo MAXX 1ME. disposing stress. 3. Bentgrass/Bermudagrass Dead Spot 3. Bentgrass/Bermudagrass Dead Spot Pathogen: Ophiosphaerella agrostis grow rell [ ofio-sfa- Pronunciation: stis ] a ] [ a- Principal hosts: Creeping bentgrass, hybrid FRAC Efficacy* Interval Code (days) Some Trade Names Fungicide: bermudagrass Emerald 7 14 boscalid: L May-October (creeping Season: 12 14 L Medallion fludioxonil: bentgrass), March-May (bermudagrass) a 33 Chipco Signature 14 fosetyl-Al: NA 11 4 14-28 pyraclostrobin: Insignia Intrinsic Only known to occur on sand-based greens and tees, 1 14 L 3336 EG thiophanate-methyl: typically on swards less than six years old or following Combination Products fumigation. Favored by heat and drought stress. May be 14 L 11 + 3 Headway, Goliath azoxystrobin + propiconazole: confused with dollar spot, copper spot, microdochium 11 + 3 ArmorTech ZOXY-T, StrobeT 14 azoxystrobin + tebuconazole: L patch, black cutworm damage, or ball marks. 7 + 11 Honor Intrinsic boscalid + pyraclostrobin: 14-28 L ConSyst, Spectro, M5 + 1 L 14 chlorothalonil + thiophanate-methyl: Broadcide, Peregrine, Tee-1-Up, TM/C pyraclostrobin + fluxapyroxad: 11 + 7 L 14-28 Lexicon 11 + 3 L 14-28 pyraclostrobin + triticonazole: Pillar a NA = not applicable. The Chipco Signature label requires tank-mixing with selected fungicides for control of bentgrass dead spot; variable control can be expected from fosetyl-Al alone. than a preventive program) during midsummer is discouraged 4. Brown Patch (Rhizoctonia Blight) because of the potential for rapid disease development and the Pathogen: Rhizoctonia solani low recuperative potential of creeping bentgrass and other -nia ] [ so- toe [ rizoc- nee ] Pronunciation: lay cool-season turfgrasses at that time of year. Ryegrasses, tall fescue, and bentgrasses Principal hosts: June-September Season: I fun - When curative control is required, consider using a Q o gicide (such as azoxystrobin or pyraclostrobin), penthiopyrad, On cool-season turf, brown patch is most severe during warm, or fluxapyroxad; expect that symptoms may increase for several humid weather, especially when night temperatures exceed days after application as previously infected tissues continue to ° 60 C). Avoid high nitrogen fertility during periods when ° F (16 develop symptoms. Applications of PCNB or mineral oil prior conditions are conducive to disease development. Periodically, to or during hot weather may cause phytotoxicity to creeping aerify and use other practices that promote good soil drainage. bentgrass and annual bluegrass. Use insecticides and herbicides Improve air circulation. The use of fans on putting greens with judiciously during an active outbreak of brown patch, as several - poor air circulation can reduce brown patch pressure dramati of them have been shown to increase brown patch activity. Vari - - cally by improving air circulation, reducing soil moisture, short ous plant growth regulators (PGRs) used on turfgrasses have ening periods of leaf wetness, and lowering canopy temperature. been shown to occasionally influence brown patch severity. On putting greens, start a preventive spray program when low In particular, applications of Cutless (flurprimidol) have been ° F (16 ° minimum air temperatures exceed 60 C) for two to three shown to reduce the efficacy of several DMI fungicides against consecutive nights (usually early-June in Central Kentucky brown patch. In several tests, chlorothalonil (e.g., Daconil Ul - and New Jersey, and late-May in Western Kentucky). During trex) has caused mild to moderate phytotoxicity on creeping the period from early-July through mid-August, when disease bentgrass, especially under acute drought stress, and severe pressure typically is highest, use products with good to excellent phytotoxicity to many fine fescue cultivars during hot weather. effectiveness against brown patch. A curative program (rather * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most 1 = no N = control is inconsistent between experiments but performs well in some instances; experiments; = fair to good control in most experiments; 2 = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 11

12 (continued) 4. Brown Patch (Rhizoctonia Blight) 4. Brown Patch a a FRAC FRAC Efficacy* Efficacy* Interval Interval Code Code (days) (days) Fungicide: Combination Products (continued) Some Trade Names b b 11 Heritage azoxystrobin: 14-28 3.5 11 + 3 Headway, Goliath azoxystrobin + propiconazole: 14/28 4/3 L 14-21 azoxystrobin + tebuconazole: 11 + 3 ArmorTech ZOXY-T, Bacillus licheniformis: EcoGuard NC 2 3-14 StrobeT NC 1 7-10 Bacillus subtilis, strain QST 713: Rhapsody boscalid + pyraclostrobin: 14-28 3.5 7 + 11 Honor Intrinsic Captan M4 L 7-10 captan: Daconil chlorothalonil + acibenzolar-S-methyl: M5 + P1 3 7-14 L 14 Terraneb SP chloroneb: 10 Action Daconil Ultrex, Manicure, Concorde chlorothalonil: M5 3 7-14 chlorothalonil + fludioxonil + propiconazole: 14-21 2.5 M5 + 12 SST, Chlorostar, Echo, Pegasus L Instrata + 3 2 fenarimol: Rubigan 3 7-14 M5 + 2 L 14-28 E-Pro ETQ, Chipco 26GT chlorothalonil + iprodione: 14 fluazinam: 29 Secure 4 + Daconil Ultrex 7 3 12 Medallion fludioxonil: 4 14-28 chlorothalonil + iprodione + thiophanate-methyl M5 + 2 + 3.5 fluoxastrobin: Fame 11 14-28 + tebuconazole: Enclave 1 + 3 flutolanil: 7 3 14-21 Prostar 14-28 chlorothalonil + propiconazole: Concert, Concert II M5 + 3 L 7 3.5 14-21 fluxapyroxad: Xzemplar chlorothalonil + tebuconazole: E-Scape ETQ M5 + 3 L 28 NC hydrogen dioxide: Zerotol 7 1 chlorothalonil + thiophanate-methyl: M5 + 1 3.5 14-21 ConSyst, 3 2 Chipco 26GT, Andersons Fungicide X, iprodione: 14-28 Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C Raven, Lesco 18 Plus, Iprodione Pro L M1 + M3 Junction copper hydroxide + mancozeb: 7-14 7 3 M3 mancozeb: Fore, Manzate 200, Protect T/O, Dithane, f fluopyram + trifloxystrobin: 7+11 Exteris Stressgard 14-28 L Pentathlon fluoxastrobin + chlorothalonil: Fame C 11 + M5 3.5 14-28 mandestrobin: 14 1.5 11 Pinpoint Disarm M 11 + 3 L 14-28 fluoxastrobin + myclobutanil: metconazole: Tourney 3 3 14-21 21-28 3.5 Fame+T 11 + 3 fluoxastrobin + tebuconazole: c mineral oil: Civitas NC 14-21 L 14-21 26/36, Dovetail, 2 + 1 iprodione + thiophanate-methyl: 1.5 myclobutanil: Eagle 3 2.5 10-21 Twosome, ArmorTech TMI d PCNB, Penstar, Terraclor, Turfcide, Revere PCNB: 7-10 14 2 iprodione + trifloxystrobin: Interface Stressgard 2 + 11 3 14-28 Velista 7 4 14-21 penthiopyrad: g PCNB + tebuconazole: Oreon 14+3 14-28 L 7-14 polyoxin D: Affirm 19 3.5 7-14 L 33 + M5 Vitalonil potassium phosphite + chlorothalonil: propiconazole: Banner Maxx, Spectator, Savvi 3 3 10-21 11 + 7 3.5 14-28 Lexicon pyraclostrobin + fluxapyroxad: pyraclostrobin: 14-28 4 11 Insignia Intrinsic pyraclostrobin + triticonazole: Pillar 11 + 3 L 14-28 7-14 1 NC Regalia PTO Reynoutria sachalinensis: thiophanate-methyl + flutolanil: SysStar 1 + 7 L 14-21 3 tebuconazole: 14-28 Torque, Mirage Stressgard, Sipcam 3 trifloxystrobin + triadimefon: 3 14-28 Armada, Tartan 11 + 3 Clearscape ETQ, Offset, ArmorTech TEB360 a NC = Not classified. 2.5 1 3336 EG, Fungo, Andersons thiophanate-methyl: 10-14 b 4 applies to two-week spray interval, 3 to four-week interval. Systemic Fungicide, Systec 1998, Cavalier, T-Storm c To reduce the potential for phytotoxicity, do not apply during hot weather thiram: Spotrete, Thiram 7-10 2 M3 (> 90°F) or periods of severe environmental stress, and do not combine 2 3 Bayleton, Andersons Fungicide VII triadimefon: 14-30 with chlorothalonil, DMI fungicides, or iron-containing products under Trichoderma harzianum Rifai T-22 plus NC L 30 high temperatures and high humidity, or tank-mix with PCNB. d Trichoderma virens G14: TurfShield PLUS To reduce phytotoxicity, do not apply to cool-season turf at daytime tem - peratures of 85°F or higher. After application, immediately irrigate with 1/4 trifloxystrobin: Compass 11 4 14-21 e inch water. 14-28 Trinity, Triton 3 triticonazole: 3/2 e Lower efficacy rating applies to tall fescue at spray intervals typical for lawn 1.5 2 14-28 vinclozolin: Curalan, Touché care. f Lightly water-in applications to move fungicide into thatch for increased Combination Products effectiveness. L 11 + P1 Heritage azoxystrobin + acibenzolar-S-methyl: 14-28 g Do not apply to cool-season turf at daytime temperatures of 85°F or higher. Action Combine with a pigment to mask chlorosis that may occur at high label rate. 14-21 azoxystrobin + chlorothalonil: Renown 11 + M5 L After application, immediately irrigate with 1/4 inch water. 14-28 11 + 3 Briskway azoxystrobin + difenoconazole: 3.5 If using thiophanate-methyl or polyoxin D, check the pH of the ment of target diseases at a later date) and has also been reported with repeated use of other fungicides such as chlorothalonil. water used to prepare spray solutions; if the pH is high, include - Fungicides may disturb a delicate balance among microorgan a buffering agent to bring the pH to between 6.0 and 7.0 to avoid isms that compete with and antagonize disease-causing fungi. reduced efficacy due to alkaline hydrolysis. This may explain why some diseases reoccur more rapidly and Avoid high rates of DMI fungicides on putting greens during cause more injury in turfs previously treated with fungicides. hot summer weather because of the possibility of undesirable growth-regulator effects (chlorosis, necrosis and/or reduced This is another reason why it is important to judiciously use and rotate fungicides with different modes of action. canopy density). Research has shown that putting green turf For high-maintenance tall fescue lawns, ready-to-use fun - exhibiting growth-regulating effects of DMI fungicides can gicide formulations available to homeowners typically have suffer significantly greater infestations of algae in summer. In one putting-green test, use of pyraclostrobin at the high labeled performed poorly in research trials (with azoxystrobin being the only known exception). Applications of azoxystrobin, fluox rate led to encroachment by algae. In another test, a fairway - tank-mix spray program consisting of Banner Maxx 1.3ME + astrobin, flutolanil, pyraclostrobin, or trifloxystrobin to lawns - have provided acceptable control of brown patch for four to five Heritage 50WG + Primo Maxx 1ME led to brown patch resur gence approximately one month after applications ended. This weeks as has the use of penthiopyrad or fluxapyroxad in several - - I fungicides gen published tests under high disease pressure. Q phenomenon is often referred to as a “latent effect” (the enhance o * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 experiments; = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 12

13 erally have performed best over four- to five-week application brown patch pressure. However, repeated applications of Dew - have caused turf yellowing in certain experiments as ® Cure intervals. Acceptable control sometimes (but not always) has been achieved using DMI (=FRAC Code 3) fungicides, such as well as increased brown patch activity. Repeated applications of DewCure propiconazole. Granular formulations of fungicidal materials ® may cause substantial phytotoxicity on annual can typically provide disease suppression but sometimes do not bluegrass putting turf when used in combination with chloro - provide complete disease control—sometimes providing less thalonil. - On several turf species, failures of fungicides (e.g., thiophan disease control in lawns than sprayable formulations. Be aware ate-methyl) that are normally effective against brown patch that chlorothalonil, iprodione, PCNB, and vinclozolin are no longer labeled for use on home lawns. Also note that fungicide may indicate the presence of Chrysorhiza zeae, the cause of products marketed for residential application by homeowners leaf and sheath spot, which can sometimes be active during hot conditions. Do not rely on thiophanate-methyl for brown patch have performed poorly in field experiments. control during hot (greater than 90 Repeated applications of commercial surfactants (such as ° C], humid conditions ° F, [3 2 ) intended to reduce dew accumulation can reduce Dew Cure ® C. zeae. favorable for 5. Brown Ring Patch 5. Brown Ring Patch Waitea circinata var. circinata Pathogen: Pronunciation: [ way- ta ] nah a ] [ sersi- tay Principal hosts: Annual bluegrass, creeping bentgrass, Efficacy* FRAC Interval Code (days) Fungicide: Some Trade Names roughstalk bluegrass a Heritage azoxystrobin: 14-28 11 3 May-September Season: a Medallion 12 fludioxonil: 7-14 3 L 14-28 Fame fluoxastrobin: 11 Damage tends to be worse on drier parts of putting 14 metconazole: Tourney 3 3 greens, especially under low fertility. Addition of a half- a Velista 14 7 penthiopyrad: L pound to 1 pound nitrogen (in any form) often helps Affirm, Endorse 19 3 7-14 polyoxin D: a promote recovery. However, use caution with nitrogen propiconazole: Banner 14-21 3 3 14-28 tebuconazole: Torque, Mirage Stressgard, Sipcam 3 3 applications during summer, to avoid favoring Pythium Clearscape ETQ, Offset, ArmorTech TEB360 and brown patch activity. Primo MAXX (trinexapac 3 14-28 triticonazole: Chipco Triton 3 ethyl) alone sometimes has increased disease slightly in Combination Products research trials, though Primo in combination with nitro - azoxystrobin + acibenzolar-S-methyl: L 11 + P1 Heritage Action 14-28 gen fertility prior to symptom development has resulted 11 + 3 azoxystrobin + difenoconazole: L Briskway 14-28 11 + 3 azoxystrobin + propiconazole: Headway, Goliath L 14-28 in substantially less disease and improved turfgrass qual - Honor Intrinsic L 14-28 boscalid + pyraclostrobin: 7 + 11 ity relative to untreated controls. Fungicides usually per - L Concert, Concert II chlorothalonil + propiconazole: M5 + 3 14-21 form better if some nitrogen fertility is in place. Based on chlorothalonil + tebuconazole: 28 L M5 + 3 E-Scape ETQ results from research trials, two applications of fungicides 14-28 fluoxastrobin + chlorothalonil: Fame C 11 + M5 L 14-28 L 11 + 3 Disarm M fluoxastrobin + myclobutanil: at a high-labeled rate may give better performance than 21-28 fluoxastrobin + tebuconazole: Fame+T 11 + 3 L one application and/or lower rates. Mixtures of labeled b PCNB + tebuconazole: Oreon 14+3 14-28 L fungicides (for example, azoxystrobin + propiconazole, L pyraclostrobin + fluxapyroxad: Lexicon 14-28 11 + 7 or polyoxin D + propiconazole) have sometimes provided 14-28 Pillar 11 + 3 L pyraclostrobin + triticonazole: a superior control as compared to the same fungicides used Labeled based on manufacturer-issued 2(ee) recommendation.: b - Do not apply to cool-season turf at daytime temperatures of 85°F or higher. Com alone. bine with a pigment to mask chlorosis that may occur at high label rate. After ap - plication, immediately irrigate with 1/4 inch water. * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most experiments; = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 13

14 chlorothalonil, fluazinam, azoxystrobin + chlorothalonil, and 6. Copper Spot propiconazole + chlorothalonil, iprodione + thiophanate- Pathogen: Gloeocercospora sorghi methyl, and DMI fungicides. Sequential applications of SDHI Pronunciation: spore-a ] [ sorg ca [ glio-sir- -ee ] fungicides such as boscalid have been shown to enhance the Principal hosts: Creeping bentgrass July-August Season: incidence and severity of copper spot. Thus SDHI fungicides should not be used, or should be tank mixed with copper spot Most severe during extended periods of hot, humid weather. fungicides, when disease pressure is high. - In limited testing, biweekly preventive applications of the fol lowing fungicides have provided good control: azoxystrobin, 6. Copper Spot (continued) 6. Copper Spot a a FRAC FRAC Efficacy* Efficacy* Interval Interval Code Code (days) (days) Combination Products (continued) Some Trade Names Fungicide: 14 L M5 + 2 E-Pro ETQ, Chipco 26GT chlorothalonil + iprodione: 7-10 4 M5 Daconil Ultrex, Manicure, Concorde chlorothalonil: + Daconil Ultrex SST, Chlorostar, Echo, Pegasus L L M5 + 2 + 14-28 chlorothalonil + iprodione + thiophanate-methyl 10-28 L fenarimol: Rubigan 3 1 + 3 Enclave + tebuconazole: Zerotol hydrogen dioxide: 7 L NC chlorothalonil + propiconazole: 4 M5 + 3 Concert, Concert II 14 L mancozeb: Protect T/O, Mancozeb, Dithane 7-14 M3 M5 + 3 E-Scape ETQ chlorothalonil + tebuconazole: L 28 3 myclobutanil: L 14 Eagle L 14 M5 + 1 chlorothalonil + thiophanate-methyl: ConSyst, L Regalia PTO 7-14 NC Reynoutria sachalinensis: Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C tebuconazole: Torque, Mirage, Sipcam Clearscape L 3 28 7-14 M1 + M3 Junction copper hydroxide + mancozeb: L ETQ, Offset, ArmorTech TEB360 Fame C fluoxastrobin + chlorothalonil: 14 L 11 + M5 thiophanate-methyl: 3336 EG, Andersons Systemic L 1 7-14 11 + 3 14-21 Disarm M fluoxastrobin + myclobutanil: L Fungicide, Systec 1998, Cavalier, T-Storm iprodione + thiophanate-methyl: 4 2 + 1 26/36, Dovetail, 14-21 triadimefon: Bayleton 15-30 L 3 Twosome, ArmorTech TMI Combination Products 14-21 thiophanate-methyl + flutolanil: L 1 + 7 SysStar azoxystrobin + chlorothalonil: Renown 14 4 11 + M5 a NC = Not classified. L M5 + P1 14 Daconil chlorothalonil + acibenzolar-S-methyl: Action results in complete loss of disease control, whereas resistance to 7. Dollar Spot DMI fungicides results in reduced efficacy or shorter intervals of Pathogen: Sclerotinia homoeocarpa control. The growth regulators paclobutrazol and flurprimidol tin a ] [ sclero- carp -ia ] [ homio- Pronunciation: slightly suppress dollar spot development, using the same bio - All turfgrasses Principal hosts: Season: Typically April-October, but can occur as late as chemical mode of action as do the DMI fungicides. Therefore, December in New Jersey avoid repeated use of DMI fungicides for dollar spot control Most severe during humid weather with moderate temperatures. combined with growth regulators containing paclobutrazol Maintain adequate nitrogen fertility. In experiments in Kentucky, or flurprimidol. This combination may enhance the risk of early morning mowing, irrigation at sunrise (when needed), DMI resistance and could also result in excessive turf growth dragging by hose, and other practices that disperse dew reduced regulation or turf chlorosis under stressful growing condi - dollar spot pressure. On fairway-height turf, an “early curative” tions. Where paclobutrazol is used on creeping bentgrass for program against this disease (application made when disease is first growth regulation, research indicates that fungicide rates can beginning to appear) can often result in less chemical use than a be reduced by 20-25% with no loss in dollar spot control. The completely preventive spray program, especially on varieties with - growth regulator trinexapac-ethyl (Primo Maxx) does not af a degree of partial resistance, such as L-93. On putting greens, fect dollar spot control when used prior to disease outbreaks; research in Michigan showed that a consistent program of light - however, it can slow turf recovery following an outbreak of the weight rolling once or twice per day, five days per week generally disease because it limits plant growth. reduces dollar spot pressure. The greatest benefit of rolling occurred Avoid high rates of DMI fungicides on putting greens during when performed twice in the morning following mowing. How - the summer because of the possibility of undesirable growth- ever, rolling once either in the morning or afternoon sometimes regulator effects (e.g., reduced turf density and/or phytotoxic - was beneficial in reducing disease pressure. On fairways, both ity). Repeated use of azoxystrobin (and other Q I fungicides) o lightweight rolling (am) and sand topdressing have been reported or flutolanil has been shown to sometimes increase dollar spot to reduce the severity of this disease in other studies. pressure, occasionally substantially. Recent studies have shown Follow practices for reducing the risk of fungicide resistance, a similar effect from the fungicides fludioxonil, polyoxin D, and as strains of resistant to benzimidazole and S. homoeocarpa L-77 surfactant. Concurrent trifloxystrobin as well as Silwet ® DMI fungicides have been found in several instances through - use of such products with DMI fungicides during weather out the U.S. Resistance to benzimidazole fungicides usually favorable for dollar spot could increase the risk of resistance to Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most * experiments; = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 14

15 greater when sprayed than when applied as granular materials. If using thiophanate-methyl, S. homoeocarpa. DMI fungicides in Monthly applications of ethephon (Proxy) have been shown to check the pH of the water used to prepare spray solutions; if the increase dollar spot pressure, although this effect was not seen pH is high, include a buffering agent to bring the pH to between where Proxy was applied with trinexapac ethyl (Primo Maxx). 4.0 and 7.0 to avoid alkaline hydrolysis. Be sure to use nozzle/ Repeated application of Insignia 20WG or Concert 4.3SC has gallonage (carrier volume) combinations to achieve thorough been associated with enhanced algal growth in certain putting- and complete spray coverage; check spray coverage using water- green experiments. Phytotoxicity to creeping bentgrass has sensitive spray paper (available online from numerous suppliers). been observed from applications of Trinity + Daconil, Reserve, In particular, contact fungicides may require application vol - Concert, and Banner MAXX + Daconil Ultrex during hot umes of 2 gal/1,000 sq ft for optimal results under high disease weather due to the DMI component of these combinations. pressure. If spraying preventively on fairways, recent research Applications of PCNB prior to or during hot weather may also suggests two applications (the second within four weeks of the cause phytotoxicity to creeping bentgrass. first) provide considerably longer control than one spray only. Repeated applications of commercial surfactants (such as Dew If attempting curative control after disease has become severe, ) intended to reduce dew accumulation can reduce dollar ® Cure fungicide mixtures (premixes or tank-mixes) are preferable spot pressure. However, Dew Cure has caused turf yellowing in for better efficacy and reduced risk of fungicide resistance. certain experiments as well as increased brown patch activity. Several studies have shown that efficacy of DMI fungicides is 7. Dollar Spot (continued) 7. Dollar Spot a a Efficacy* Efficacy* FRAC FRAC Interval Interval Code Code (days) (days) Fungicide: Some Trade Names Combination Products (continued) EcoGuard 2 3-14 NC Bacillus licheniformis: 14-28 3.5 7 + 11 Honor Intrinsic boscalid + pyraclostrobin: NC 1 Bacillus subtilis, strain QST 713: Rhapsody 7-10 M5 + P1 3.5 7-21 chlorothalonil + acibenzolar-S-methyl: b Daconil Action 7 Emerald 14-28 boscalid: 4/3.5 21-28 chlorothalonil + fludioxonil + propiconazole: M5 + 12 4 7-14 Daconil Ultrex, Manicure, 3 chlorothalonil: M5 + 3 Instrata Concorde SST, Chlorostar, Echo, Pegasus L E-Pro ETQ, Chipco 14-28 M5 + 2 chlorothalonil + iprodione: L 3 10-30 fenarimol: Rubigan 3 26GT + Daconil Ultrex fluazinam: Secure 29 4 14 14-28 M5 + 2 + chlorothalonil + iprodione + thiophanate- 3.5 11 Fame 14-21 3 fluoxastrobin: 1 + 3 methyl + tebuconazole: Enclave Xzemplar 14-28 4 7 fluxapyroxad: chlorothalonil + propiconazole: Concert, M5 + 3 4 14-28 NC hydrogen dioxide: 7 Zerotol 1 Concert II 2 14-28 iprodione: Chipco 26GT, Raven, Lesco 18 Plus, 3.5 E-Scape ETQ chlorothalonil + tebuconazole: L 28 M5 + 3 Iprodione Pro M5 + 1 14-21 chlorothalonil + thiophanate-methyl: 3.5 3.5 7 Kabuto 14 isofetamid: ConSyst, Spectro, Broadcide, Peregrine, Tee-1- Fore, Protect T/O, Dithane, mancozeb: 7-14 M3 1 Up, TM/C Mancozeb Junction 7-14 L M1 + M3 copper hydroxide + mancozeb: b 14-21 mandestrobin: 11 Pinpoint 4/3.5 fluopyram + trifloxystrobin: 4 7-28 Exteris Stressgard 7+11 metconazole: Tourney 3 4 14-21 11 + M5 L Fame C fluoxastrobin + chlorothalonil: 14-21 c NC Civitas mineral oil: 7-21 2 11 + 3 Disarm M L fluoxastrobin + myclobutanil: 14-21 myclobutanil: Eagle 3 3.5 14-28 Fame+T 3 fluoxastrobin + tebuconazole: 21-28 11 + 3 d 21-28 PCNB, Penstar, Terraclor, Turfcide, PCNB: 14 L 2 + 1 iprodione + thiophanate-methyl: 26/36, 14-21 4 Revere Dovetail, Twosome, ArmorTech TMI penthiopyrad: Velista 7 3.5 14-21 2 + 11 14-28 4 Interface iprodione + trifloxystrobin: propiconazole: Banner Maxx, Spectator, Savvi 3 4 7-28 Stressgard Insignia Intrinsic pyraclostrobin: 11 3.5 14 f PCNB + tebuconazole: 14+3 14-28 Oreon 1.5 NC 1.5 7-14 Regalia PTO Reynoutria sachalinensis: L 33 + M5 potassium phosphite + chlorothalonil: 7-10 14-28 tebuconazole: Torque, Mirage Stressgard, 3 4 Vitalonil Sipcam Clearscape ETQ, Offset, ArmorTech 3.5 Lexicon pyraclostrobin + fluxapyroxad: 14-28 11 + 7 TEB360 L Pillar 11 + 3 pyraclostrobin + triticonazole: 14-28 e 3336 EG, Fungo, thiophanate-methyl: 1 10-21 1/4 14-30 1 + 7 SysStar thiophanate-methyl + flutolanil: L Andersons Systemic Fungicide, Systec 1998, 14-28 3.5 11 + 3 Armada, Tartan trifloxystrobin + triadimefon: Cavalier, T-Storm a 7-10 1 M3 thiram: Spotrete, Thiram, Defiant NC = Not classified. b 4 applies to two-week spray interval, 3.5 to three or four week intervals. 14-30 triadimefon: Bayleton, Andersons Fungicide 3 4 c - Efficacy is higher with shorter labeled spray intervals. To reduce the poten VII tial for phytotoxicity, do not apply during hot weather (> 90°F) or periods of 7-14 NC Trichoderma harzianum Rifai T-22 plus 1 severe environmental stress, and do not combine with chlorothalonil, DMI Trichoderma virens G14: TurfShield PLUS fungicides, or iron-containing products under high temperatures and high 3 3.5 Trinity, Triton triticonazole: 14-28 humidity, or tank-mix with PCNB. d Curalan, Touché, Vorlan 2 4 14-28 vinclozolin: To reduce phytotoxicity, do not apply to cool-season turf at daytime tem - peratures of 85°F or higher. Combination Products e Lower efficacy rating applies when isolates of S. homoeocarpa resistant to 11 + M5 7-14 Renown 3.5 azoxystrobin + chlorothalonil: thiophanate methyl are present. Resistance is very common in numerous 11 + 3 azoxystrobin + difenoconazole: Briskway 14-21 3 locations in the U.S. Resistance to iprodione and reduced sensitivity to the DMI fungicides has also been reported. 14-28 Headway, azoxystrobin + propiconazole: 3.5 11 + 3 f Do not apply to cool-season turf at daytime temperatures of 85°F or higher. Goliath Combine with a pigment to mask chlorosis that may occur at high label rate. 14-21 ArmorTech azoxystrobin + tebuconazole: L 11 + 3 After application, immediately irrigate with 1/4 inch water. ZOXY-T, StrobeT * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most experiments; = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 15

16 In several experiments, improved control of dollar spot has been performance against dollar spot similar to that provided by chlorothalonil alone. However, in a number of experiments, this achieved using reduced rates of conventional fungicides when products were co-applied with Civitas/Harmonizer. In several product provided somewhat longer residual control or somewhat better efficacy than that provided by chlorothalonil alone. Recent experiments, Civitas + Harmonizer alone and in combination with research at Rutgers has shown that the fungicide boscalid was a propiconazole/chlorothalonil tank-mix resulted in phytotoxicity - during hot weather. The same combination has also been associ more efficacious (longer intervals of control and fewer applica - tions per year) when applied to more dollar spot tolerant cultivars ated with enhanced algal growth on a putting green presumably due to the thinning associated its use during heat stress. (Declaration, 007, Shark, Capri) compared to more sensitive cultivars (Independence and Penncross). Thus select cultivars The fungicide product Daconil Action, a premix of chloro - with improved tolerance to dollar spot whenever renovating sites. thalonil and acibenzolar-S-methyl, often has provided efficacy 8. Fairy Ring 8. Fairy Ring * b Pathogen: A complex of basidiomycete fungi a my -seat ] [ ba- sid io- Pronunciation: All turfgrasses Principal hosts: FRAC Efficacy Interval Code (days) Some Trade Names Fungicide: All year Season: Heritage 28 3 azoxystrobin: 11 fluoxastrobin: Fame 11 L 21-28 Fertilize with nitrogen or iron and irrigate appropriately to flutolanil: 3 30 7 Prostar mask symptoms; reduce thatch. Attempt to manage putting L hydrogen dioxide: Zerotol NC 7 - greens with fairy ring problems so that they have a steady, con 14 mandestrobin: Pinpoint 11 L sistent moisture supply in the root zone rather than experiencing 3 metconazole: Tourney 3 21 c 14-28 penthiopyrad: Velista 7 L regular extremes of a very wet root zone alternating with a dry polyoxin D: 7 Affirm 19 2.5 root zone. Fungicide use to suppress symptoms is not recom - pyraclostrobin: 3 28 11 Insignia Intrinsic mended except on putting greens or other turfs managed at d 3 28 tebuconazole: Torque, Mirage Stressgard, L or below 0.25 inch height of cut. The fungicides listed in the Sipcam Clearscape ETQ, Offset, ArmorTech TEB360 accompanying table suppress growth of some of the fungi that 14-21 3 3 Bayleton FLO triadimefon: cause fairy ring, but aerification, adequate nitrogen fertility, use Combination Products of a wetting agent, and judicious irrigation may be necessary to azoxystrobin + acibenzolar-S-methyl: 28 L 11 + P1 Heritage alleviate symptoms. Aerification prior to fungicide application Action 14-28 azoxystrobin + difenoconazole: Briskway 11 + 3 L may sometimes improve efficacy by improving soil penetration. azoxystrobin + propiconazole: L 11 + 3 Headway, 14-28 Apply the fungicides in 2-4 gal of water/1,000 sq ft (or more, if Goliath required by the label). Some studies indicate the importance of azoxystrobin + tebuconazole: 28 L 11 + 3 ArmorTech ZOXY-T, StrobeT high-volume applications as well as inclusion of a wetting agent 7 + 11 L 28 Honor Intrinsic boscalid + pyraclostrobin: - (either the day before application or tank-mixed with the fungi L fluoxastrobin + chlorothalonil: 21-28 11 + M5 Fame C cide) for both preventive as well as curative applications. However, 11 + 3 L Disarm M fluoxastrobin + myclobutanil: 21-28 research is mixed on these points, since other studies suggest that 11 + 3 Fame+T L 21-28 fluoxastrobin + tebuconazole: e 28 PCNB + tebuconazole: Oreon 14+3 L high spray volumes and wetting agents may not improve control. pyraclostrobin + fluxapyroxad: Lexicon 11 + 7 L 28 Wetting agents should not be tank-mixed with DMI fungicides, Pillar 14-28 pyraclostrobin + triticonazole: 11 + 3 L as these fungicides increase the potential for phytotoxicity and 1-2x @ L 1 + 7 SysStar thiophanate-methyl + flutolanil: may reduce efficacy. Unless the label specifies otherwise, applying 21-28 11 + 3 L Armada, Tartan 1-2x @ 28 trifloxystrobin + triadimefon: 0.25 inch of irrigation immediately after fungicide application a NC = Not classified. (before the fungicide has a chance to dry) helps with fungicide b Efficacy rating assumes application with a wetting agent in at least 2 gal penetration, although studies are mixed on the importance of water/1000 sq ft. c Labeled based on manufacturer-issued 2(ee) recommendation. this practice, as well. Within label limits, frequent applications d Disease not listed on federal label but may be used in accordance with at lower rates may give better control than higher rates applied manufacturer-issued 2(ee) recommendation. e - Do not apply to cool-season turf at daytime temperatures of 85°F or high infrequently. In some (but not all) tests, application of wetting er. Combine with a pigment to mask chlorosis that may occur at high label agents alone such as Revolution or Cascade Plus alleviated rate. After application, immediately irrigate with 1/4 inch water. symptoms somewhat. In certain tests, Revolution has resulted in North Carolina suggest that the optimal time to make the first - increased populations of mushrooms or has caused phytotoxic application in spring is when the five-day average soil temperature ity. In some research trials, applications in early spring of DMI ° reaches 55-60 C). A second application 30 days later F (13 -16 ° fungicides (Bayleton 4SC or Banner Maxx) with post-application may sometimes be necessary for season-long control. Although irrigation caused temporary phytotoxicity to creeping bentgrass flutolanil is often effective, in at least one research trial testing - later in summer during hot, dry conditions. Recognize that nu curative applications, this fungicide enhanced fairy ring pressure merous fungi can cause fairy rings. Some of these fungi may not rather than reducing it (highlighting the difficulty in planning a be sensitive to these fungicides at normal use rates; others may control program for this disease complex). be too deep in the soil to be affected by the fungicide. Studies in * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most = control is inconsistent between experiments but performs well in some instances; = no N experiments; 1 = fair to good control in most experiments; 2 = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 16

17 with moderate efficacy can and should be used for applications 9. Gray Leaf Spot on either side of this treatment window; they should also be used Pyricularia oryzae (Pyricularia grisea) Pathogen: as mixing partners with highly efficacious compounds during Pronunciation: lar rise -ia ] [ o- -ee ] [ pie-ricku- -sea-a ] [ pie-ricku- lar -ia ] [ gri the period when logarithmic increase is possible. Tank-mixes of Principal host: Perennial ryegrass, tall fescue - propiconazole (Banner Maxx 1.3ME at 1 fl oz/1,000 sq ft) or tri July-September Season: adimefon (Bayleton 50WP at 1 oz/1,000 sq ft) with chlorothalonil Develops during warm, humid weather in mid- to late-summer (Daconil Ultrex 82.5WDG at 3.2 oz/1,000 sq ft, for example) can - and early-autumn. Perennial ryegrass is generally more sus provide superior control as compared to the individual products. ceptible than tall fescue. Keep nitrogen fertility low during the Similarly, a tank-mix of azoxystrobin (Heritage TL 0.8ME at 1 fl summer to reduce susceptibility; apply a total of no more than 0.5 oz) + chlorothalonil (Daconil Ultrex 82.5WDG at 3.2 oz/1,000 lb N/1,000 sq ft during spring and summer. The disease is more sq ft) has consistently provided better control in research trials in severe at higher cutting heights, so scout roughs when weather New Jersey compared to the individual components alone, even is conducive to infection to detect the first outbreaks of gray leaf when Q I resistant isolates were present. o spot on golf courses. Use resistant perennial ryegrass or tall fescue To minimize the risk of fungicide resistance, rotate frequently cultivars when seeding new areas or overseeding existing swards. among fungicides having different modes of action. The wisest To reduce disease potential, delay seedings until minimum night- strategy is to switch after only one application of any given ° time air temperatures are consistently below 65 F (18 ° C). Fu ng i - systemic mode of action, especially with Q I fungicides or o cide protection is generally necessary under Kentucky and New - thiophanate-methyl. Also advisable in reducing the risk of fun Jersey conditions, especially during August and early September gicide resistance is to tank-mix these fungicides with a contact when explosive (logarithmic) disease increase is possible. During fungicide when using them for gray leaf spot control. the period of logarithmic increase, only fungicides with high ef - Newly emerged ryegrass seedlings in swards damaged by gray ficacy are recommended. However, excessive reliance on the Q I leaf spot are most susceptible four to five weeks post-emergence o and benzimidazole fungicides runs a substantial risk of selecting and often need fungicidal protection until sustained periods of Therefore, compounds fungicide-resistant strains of P. oryzae. cool, dry weather develop in autumn. One study suggests that 9. Gray Leaf Spot 9. Gray Leaf Spot (continued) a a Efficacy* FRAC FRAC Efficacy* Interval Interval Code Code (days) (days) Combination Products (continued) Some Trade Names Fungicide: b Heritage 14-21 11 azoxystrobin: L 14-28 M5 + 2 + chlorothalonil + iprodione + thiophanate- 1/4 methyl + tebuconazole: Enclave 1 + 3 2.5 chlorothalonil: Daconil Ultrex, Manicure, Echo, M5 7-10 M5 + 3 Concert, chlorothalonil + propiconazole: 14-21 2.5 Pegasus L b Concert II fluoxastrobin: Fame 11 14-28 1/3.5 28 E-Scape ETQ M5 + 3 L chlorothalonil + tebuconazole: 14 mancozeb: Fore M3 2 14 chlorothalonil + thiophanate-methyl: ConSyst, 4 M5 + 1 metconazole: Tourney 3 2 14 Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C c 14 NC Civitas mineral oil: 2.5 7+11 L fluopyram + trifloxystrobin: Exteris Stressgard 14-28 polyoxin D: Affirm 19 1 7-14 14-28 11 + M5 Fame C fluoxastrobin + chlorothalonil: L 14 2 propiconazole: Banner Maxx, Spectator, Savvi 3 fluoxastrobin + myclobutanil: 14-28 L 11 + 3 Disarm M b 14-28 11 Insignia Intrinsic pyraclostrobin: 1/4 L 11 + 3 Fame+T fluoxastrobin + tebuconazole: 21-28 Reynoutria sachalinensis: Regalia PTO NC L 7-14 Fore Rainshield + M3 + M5 3 14 mancozeb + chlorothalonil: 3 2.5 14-28 Torque, Mirage Stressgard, tebuconazole: Daconil Ultrex Sipcam Clearscape ETQ, Offset, ArmorTech d PCNB + tebuconazole: Oreon 14+3 14-28 L TEB360 potassium phosphite + chlorothalonil: 7-10 33 + M5 L thiophanate-methyl: 3336 EG, Fungo 1 7-14 4 Vitalonil 3 Bayleton 50 2 14 triadimefon: L 14-28 pyraclostrobin + fluxapyroxad: Lexicon 11 + 7 b 11 14-21 Compass trifloxystrobin: 1/3+ Pillar L 11 + 3 pyraclostrobin + triticonazole: 14-28 Combination Products 14 thiophanate-methyl + flutolanil: SysStar 1 + 7 L 11 + P1 L 14-28 azoxystrobin + acibenzolar-S-methyl: 3 Bayleton 50 + 3 + M5 14 triadimefon + chlorothalonil: Heritage Action Daconil Ultrex 3.5 Renown, 10-14 azoxystrobin + chlorothalonil: 11 + M5 L 11 + 3 Armada, Tartan trifloxystrobin + triadimefon: 14-28 Heritage + Daconil, Heritage Action + Daconil a NC = Not classified. Action b - Lower efficacy rating applies when isolates of P. oryzae resistant to azoxys 11 + 3 Briskway azoxystrobin + difenoconazole: L 14-21 - trobin (and related Q I fungicides) are present. Resistance has been re o b azoxystrobin + propiconazole: Headway, 11 + 3 14-28 2.5/3.5 ported to occur in some years and not others in the same location, thus it Goliath I fungicides with other products labeled for the control is best to apply Q o 11 + 3 ArmorTech azoxystrobin + tebuconazole: L 14-21 of this disease. c ZOXY-T, StrobeT To reduce the potential for phytotoxicity, do not apply during hot weather (> 90°F) or periods of severe environmental stress, and do not combine boscalid + pyraclostrobin: Honor Intrinsic 7 + 11 L 14-28 with chlorothalonil, DMI fungicides, or iron-containing products under L M5 + P1 chlorothalonil + acibenzolar-S-methyl: 7-14 high temperatures and high humidity, or tank-mix with PCNB. Daconil Action d - Do not apply to cool-season turf at daytime temperatures of 85°F or high 14 chlorothalonil + fludioxonil + propiconazole: L M5 + 12 er. Combine with a pigment to mask chlorosis that may occur at high label + 3 Instrata rate. After application, immediately irrigate with 1/4 inch water. chlorothalonil + iprodione: E-Pro ETQ, Chipco M5 + 2 L 14-28 26GT + Daconil Ultrex Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most * experiments; = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 17

18 efficacy of azoxystrobin deteriorates when the turf is under in isolated locations in Kentucky and elsewhere depending on - her extreme drought stress. The high labeled rate of Prograss the year; resistant strains may be transported as conidia to sites ™ by winds in some years but not others. Q bicide applied in spring to perennial ryegrass has been shown I fungicides remain an o to somewhat enhance gray leaf spot damage. Consider using important tool for combating gray leaf spot; however, monitor the lower rate of Prograss as split applications in the spring. If treated areas for unexpected disease outbreaks. Under severe disease pressure, use of premixes or tank-mixes of fungicides using thiophanate-methyl, check the pH of the water used to with different modes of action may help reduce the risk of fun - prepare spray solutions; if the pH is high, include a buffering agent to bring the pH to between 4.0 and 7.0 to avoid alkaline gicide resistance and improve efficacy, especially if tank-mixes I-resistant strains of hydrolysis. Q are rotated with each application. have been detected P. oryzae o 10. Large Patch of Zoysia (formerly Zoysia Patch) (formerly Zoysiagrass 10. Large Patch of Zoysiagrass Patch) a Rhizoctonia solani Pathogen: [ rizoc- toe -nia ] [ so- lay nee ] Pronunciation: tions (x) Efficacy* FRAC Interval Code (days) or Applica- Fungicide: Some Trade Names Zoysiagrass, bermudagrass Principal hosts: 3 11 azoxystrobin: Heritage 28 L 21-28 chloroneb: 14 Terraneb SP April-June and September-October Season: flutolanil: 30 Prostar 7 4 Favored by chronic high soil moisture and close mowing. L Xzemplar fluxapyroxad: 7 14-28 Bermudagrass is less susceptible and quicker to recover than iprodione: 14-21 2 2 Chipco 26GT, Raven, Lesco 18 Plus, Iprodione Pro zoysiagrass. Improve drainage in affected fairways by filling low Tourney 3 L 14 metconazole: areas or installing tile drainage. Avoid over-irrigation, especially Civitas mineral oil: Sept. and L NC in spring and autumn. Avoid adding nitrogen fertilizer in Sep - Oct. before dormancy tember or during periods in spring when the disease is visibly 2.5 3 Eagle myclobutanil: 28 active (indicated by a bright orange color at the patch margin). PCNB: PCNB, Penstar, Terraclor, Turfcide 14 4 21-28 On fairways, raise the mowing height by 0.25 inch in mid- to Velista 14-28 penthiopyrad: 7 3 late-September. Some observations suggest that mowing when 7-14 polyoxin D: Affirm 19 1.5 3 2 1x Banner Maxx, Spectator, Savvi propiconazole: the turf is soggy and growing slowly increases disease activ - 11 3 14-28 pyraclostrobin: Insignia Intrinsic ity. Aerify during the peak of summer, when the large patch NC L 7-14 Reynoutria sachalinensis: Regalia PTO fungus is relatively inactive, since aerifying in early summer or Torque, Mirage Stressgard, Sipcam tebuconazole: 3.5 3 1-2x @ 28 Clearscape ETQ, Offset, ArmorTech TEB360 late summer can result in spread of the disease. Studies suggest 3 4 1x triadimefon: Bayleton that disease development is not influenced by nitrogen rate and 14-28 triticonazole: Trinity, Triton 3 3 source or by pre-emergence herbicides. Combination Products On sites with a history of the disease, studies consistently 11 + P1 azoxystrobin + acibenzolar-S-methyl: Heritage L 14-28 show that at least one application in autumn is critical to Action 11 + M5 L 14-21 azoxystrobin + chlorothalonil: Renown successful control in high-pressure sites. Recent observations azoxystrobin + difenoconazole: 11 + 3 L 14-28 Briskway indicate that the disease can be active as early as the first week 11 + 3 L azoxystrobin + propiconazole: Headway, Goliath 14-28 in August, earlier than in previous decades. It is unknown why ArmorTech ZOXY-T, 11 + 3 L 1-2x @ 14-21 azoxystrobin + tebuconazole: StrobeT the epidemiology of this disease is changing, but fungicide L boscalid + pyraclostrobin: Honor Intrinsic 7 + 11 14-28 use recommendations are currently dynamic as we continue 14-21 E-Pro ETQ, Chipco chlorothalonil + iprodione: M5 + 2 L to learn more about this disease. At this time, perhaps the 26GT + Daconil Ultrex most rational use of preventive fungicides is to carefully map M5 + 2 + L chlorothalonil + iprodione + thiophanate- 14-28 Enclave 1 + 3 methyl + tebuconazole: affected areas of the course and to treat these in late August chlorothalonil + tebuconazole: E-Scape ETQ M5 + 3 L 28 to early September. A second or even third treatment is often fluoxastrobin + chlorothalonil: Fame C 11 + M5 L 14-28 valuable. Timing windows for additional applications include 21-28 L 11 + 3 Disarm M fluoxastrobin + myclobutanil: L 2 + 11 14-21 iprodione + trifloxystrobin: Interface Stressgard 4-6 weeks after the first application and/or in early spring. All b 14+3 Oreon 28 PCNB + tebuconazole: L three applications in all three times may be necessary under 11 + 7 L 14-28 Lexicon pyraclostrobin + fluxapyroxad: high disease pressure. If applying curatively (after disease has 11 + 3 L 1-2x @ 14-28 pyraclostrobin + triticonazole: Pillar developed) in autumn, the application may not show a benefit a NC = Not classified. b until mid-spring, but curative applications of effective products Do not apply to cool-season turf at daytime temperatures of 85°F or higher. Combine with a pigment to mask chlorosis that may occur at high label rate. in autumn certainly can provide some disease control the fol - After application, immediately irrigate with 1/4 inch water. lowing season. Re-treatment in early spring is often necessary centers of fairways, newly established zoysiagrass). If applying fun - on high-maintenance zoysiagrass fairways, especially if sustained gicide to zoysiagrass in the spring, make the application when the wet weather occurs in spring. Re-treatment in springtime is first indication of active disease (a bright orange color at the patch of greatest value on sites where there is a substantial threat of margin) is observed. On bermudagrass, late-spring fertilization bermudagrass encroachment into the thinned zoysiagrass areas; with nitrogen will help many swards outgrow the damage without applications are of less value on sites without such a risk (such as * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most = no N = control is inconsistent between experiments but performs well in some instances; experiments; = fair to good control in most experiments; 2 1 = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 18

19 application if clippings are not being removed. In limited research, the need for springtime application of fungicide. Use the highest labeled rate of the product selected, and apply in a minimum of 2.5 a premix of azoxystrobin + propiconazole was more effective than one of trifloxystrobin + triadimefon (source PDMR 8:T019). gal of water/1,000 sq ft. There is no need to irrigate or syringe after 11. Leaf Smuts (Stripe Smut, Flag Smut) 11. Leaf Smuts (Stripe Smut, Flag Smut) and Urocystis agropyri Ustilago striiformis Pathogen: a [ u-still- mis ] for go ] [ stria- ah Pronunciation: tis ] [ agro- sis -ree ] pie [ euro- tions (x) Efficacy* FRAC Interval Code (days) or Applica- Fungicide: Some Trade Names Principal hosts: Kentucky bluegrass 3 1x Rubigan L fenarimol: Season: April-November 7 hydrogen dioxide: Zerotol NC L 3 1-2x myclobutanil: Eagle 3 Avoid high nitrogen. Renovate with resistant varieties of propiconazole: 1x Banner Maxx, Spectator, Savvi 3 3 Kentucky bluegrass or with tall fescue, which is not affected. 1x tebuconazole: L 3 Torque, Sipcam Clearscape ETQ, Stripe smut may be enhanced by applications of chlorothalonil Offset, ArmorTech TEB360 thiophanate-methyl: 3336 EG, Fungo, T-Storm 1 3 2x or thiram. Apply fungicide in early- to mid-October; water-in 1x 3 triadimefon: Bayleton 3 before product dries on the leaf. A single, well-timed application Combination Products in early- to mid-October is far superior to multiple applications 14-28 M5 + 2 + L chlorothalonil + iprodione + thiophanate- in the spring. Control of these diseases is very difficult with methyl + tebuconazole: 1 + 3 Enclave springtime applications of fungicides. See label for specific smut Concert, M5 + 3 1x chlorothalonil + propiconazole: L Concert II diseases controlled. L M5 + 3 E-Scape ETQ chlorothalonil + tebuconazole: 1x a NC = Not classified. Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; * 3 = good to excellent control in most = fair to good control in most experiments; 2 experiments; 1 = control is inconsistent between experiments but performs well in some instances; = no N + = limited published data on effectiveness; L efficacy; = intermediate between two efficacy categories. 19

20 12. Leaf Spots and Melting Out 12. Leaf Spot and Melting Out and Drechslera spp. ( Helminthosporium Pathogen: Bipolaris a spp.) lar Pronunciation: [ bipo- is ] FRAC Efficacy* Interval Code (days) Some Trade Names Fungicide: dreck -slurra ] [ 3.5 14-21 Heritage azoxystrobin: 11 -ium ] [ hel-mintho- spore captan: M4 L Captan 7-10 Principal hosts: All turfgrasses 3 7-10 Daconil Ultrex, Manicure, Concorde chlorothalonil: M5 April-October Season: SST, Chlorostar, Echo, Pegasus L fluazinam: Secure 29 3 14 Avoid high nitrogen fertility and excessive thatch. Water Medallion 14-21 12 fludioxonil: 3.5 deeply and infrequently to avoid drought stress. Renovate with 14-21 3 11 Fame fluoxastrobin: improved, disease resistant cultivars. Where necessary, apply 7 hydrogen dioxide: Zerotol NC L fungicides preventively. For curative applications, use products 2 iprodione: Chipco 26GT, Andersons Fungicide X, 3.5 14-28 Raven, Lesco 18 Plus, Iprodione Pro rated as 4 in the accompanying table. On high-maintenance 3.5 Fore, Manzate 200, Protect T/O, M3 7-14 mancozeb: perennial ryegrass, leaf spotting leading to leaf blighting Dithane, Pentathlon b can develop anytime extended periods of wet weather with mineral oil: NC Civitas 14 L myclobutanil: Eagle 3 1 14 temperatures in the 50s and lower 60s (°F) occur (depending 2 14 PCNB, Penstar, Terraclor, Turfcide, Revere PCNB: 21-28 on weather, from March through early June). Applications of 14 penthiopyrad: Velista 7 3.5 thiophanate-methyl, triadimefon or other DMI fungicides may polyoxin D: Affirm 19 L 7-14 increase disease pressure. Certain fungicides or formulation of propiconazole: Banner Maxx, Spectator, Savvi 3 1.5 14 14-28 3 11 Insignia Intrinsic pyraclostrobin: products are labeled for only one phase (i.e., leaf spot or melting 3336 EG, Systec 1998, 7-14 1 thiophanate-methyl: 1 out) of this disease. Where red leaf spot (caused by Drechslera Cavalier, T-Storm erythrospila ) is active on creeping bentgrass, azoxystrobin has trifloxystrobin: Compass 11 2.5 14-28 been shown to be effective; flutolanil can enhance pressure from 14-28 triticonazole: Trinity, Triton 3 L Curalan, Touché, Vorlan vinclozolin: 2 14-28 3.5 red leaf spot on creeping bentgrass. Limited studies have shown Combination Products poor control of Bipolaris sorokiniana on creeping bentgrass with 11 + P1 14-21 3.5 Heritage azoxystrobin + acibenzolar-S-methyl: the combination of triticonazole + chlorothalonil. Action In bermudagrass, phytotoxicity has been caused by sum - 14-21 11 + M5 L Renown azoxystrobin + chlorothalonil: Briskway azoxystrobin + difenoconazole: L 11 + 3 14-21 mertime applications of certain DMI fungicides (FRAC Code Headway, Goliath 11 + 3 14-21 L azoxystrobin + propiconazole: 3; specifically, products containing metconazole, propiconazole, ArmorTech ZOXY-T, 11 + 3 azoxystrobin + tebuconazole: L 14-21 tebuconazole, triadimefon, or triticonazole) (source=PDMR StrobeT 8 :T010). 7 + 11 boscalid + pyraclostrobin: 14-28 Honor Intrinsic L chlorothalonil + acibenzolar-S-methyl: 7-21 M5 + P1 Daconil L Action L 14-21 chlorothalonil + fludioxonil + propiconazole: M5 + 12 Instrata + 3 L M5 + 2 chlorothalonil + iprodione: 14-28 E-Pro ETQ, Chipco 26GT + Daconil Ultrex Concert, Concert M5 + 3 L 14-21 chlorothalonil + propiconazole: II M5+ 1 L 14 chlorothalonil + thiophanate-methyl: ConSyst, Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C Junction M1 + M3 copper hydroxide + mancozeb: L 7-14 fluoxastrobin + chlorothalonil: L 14-21 11 + M5 Fame C Disarm M 11 + 3 L 14-28 fluoxastrobin + myclobutanil: 21-28 Fame+T 11 + 3 L fluoxastrobin + tebuconazole: 26/36, Dovetail, 2 + 1 iprodione + thiophanate-methyl: L 14-21 Twosome, ArmorTech TMI Interface Stressgard iprodione + trifloxystrobin: 3.5 14-28 2 + 11 33 + M5 Vitalonil potassium phosphite + chlorothalonil: 7-10 L Lexicon 11 + 7 3.5 14-28 pyraclostrobin + fluxapyroxad: L 14-28 11 + 3 Pillar pyraclostrobin + triticonazole: thiophanate-methyl + flutolanil: SysStar 1 + 7 14 L Armada, Tartan 11 + 3 trifloxystrobin + triadimefon: 14-28 L a NC = Not classified. b To reduce the potential for phytotoxicity, do not apply during hot weather (> 90°F) or periods of severe environmental stress, and do not combine with chlorothalonil, DMI fungicides, or iron-containing products under high temperatures and high humidity, or tank-mix with PCNB. * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most experiments; = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 20

21 13. Necrotic Ring Spot 13. Necrotic Ring Spot Ophiosphaerella korrae Pathogen: a a ] [ -ee ] core Pronunciation: [ ofio-sfa- rell Principal hosts: Kentucky bluegrass,annual bluegrass, tions (x) FRAC Efficacy* Interval Code (days) or Applica- Some Trade Names Fungicide: red fescue Heritage 11 L 14-28 azoxystrobin: Season: March-June and September-October 3 1-2x fenarimol: Rubigan 3 Fame fluoxastrobin: 11 L 14-28 Control thatch buildup and reduce compaction. 14-21 iprodione: Chipco 26GT, Raven, Lesco 18 Plus, Iprodione Pro 2 2 Avoid high nitrogen fertility, particularly in spring b NC 14 mineral oil: Civitas L and summer. Irrigate to prevent drought stress. 3 28 Eagle myclobutanil: 3 - Although deep and infrequent irrigation is recom Banner Maxx, Spectator, Savvi 3 propiconazole: 2 28 14-28 L 11 Insignia Intrinsic pyraclostrobin: mended for management of most turf diseases, light L Torque, Mirage Stressgard, Sipcam tebuconazole: 3 28 and frequent irrigation can promote survival after Clearscape ETQ, Offset, ArmorTech TEB360 an outbreak of necrotic ring spot, since the disease 10-14 1 3336 EG, Fungo, Systec 1998, T-Storm thiophanate-methyl: 2 results in a shallow (more drought sensitive) root Combination Products Heritage Action 11 + P1 L 14-28 azoxystrobin + acibenzolar-S-methyl: system. It may also help to apply this irrigation during 11 + 3 L Briskway azoxystrobin + difenoconazole: 14-28 the hottest part of the day. Maintain a mowing height 14-28 Headway, Goliath 11 + 3 azoxystrobin + propiconazole: L no lower than 2 inches. Apply fungicides in April/ L 14-21 azoxystrobin + tebuconazole: 11 + 3 ArmorTech ZOXY-T, StrobeT May, and water-in prior to drying on leaves. Overseed L 7 + 11 boscalid + pyraclostrobin: 14-28 Honor Intrinsic M5 + 2 L 28 E-Pro ETQ, Chipco 26GT + chlorothalonil + iprodione: affected areas with perennial ryegrass, or renovate Daconil Ultrex with resistant varieties of Kentucky bluegrass or chlorothalonil + iprodione + thiophanate-methyl + M5 + 2 + 14-28 L with tall fescue. Applications of chlorothalonil may tebuconazole: Enclave 1 + 3 E-Scape ETQ chlorothalonil + tebuconazole: 28 L M5 + 3 enhance disease pressure. L fluoxastrobin + chlorothalonil: Fame C 11 + M5 14=28 14-28 iprodione + trifloxystrobin: 2 + 11 L Interface Stressgard c Oreon 28 14+3 PCNB + tebuconazole: L Lexicon pyraclostrobin + fluxapyroxad: 11 + 7 L 14-28 L pyraclostrobin + triticonazole: Pillar 28 11 + 3 a NC = Not classified. b To reduce the potential for phytotoxicity, do not apply during hot weather (> 90°F) or periods of severe environmental stress, and do not combine with chlorothalonil, DMI fungicides, or iron-containing products under high temperatures and high humidity, or tank-mix with PCNB. c Do not apply to cool-season turf at daytime temperatures of 85°F or higher. Combine with a pigment to mask chlorosis that may occur at high label rate. After application, immediately irrigate with 1/4 inch water. which can lead to lodging and enhanced disease development. Do 14. Pink Snow Mold/Microdochium Patch (Fusarium Patch) not leave turf uncut in late autumn or winter. Remove mulches of Pathogen: Microdochium nivale (Fusarium nivale) fallen leaves. Control drifting snow with the use of snow fences. -lee ] vah -ium ] [ nee- Pronunciation: [ micro- doke -ium ] [ nee- sar [ fyu- -lee ] vah On new bentgrass seedings, provide conditions favorable for Principal hosts: Creeping bentgrass, annual bluegrass, perennial good drainage; begin spraying in early-November before turf ryegrass, Kentucky bluegrass, fine fescues goes dormant and continue at four-week intervals provided Season: November-May; can occur any time of year C) there is no snow cover until temperatures exceed 60 ° F (16 ° in the Pacific Northwest when conditions are conducive to infection ° F, [18 C], if the disease has ° during rain events in the spring (or 65 recently been active). On established bentgrass that consistently Common on greens and fairways seeded the previous summer experiences the disease, apply a fungicide preventively in early- or autumn. Can also be destructive in one year-old or even older to mid-November and then repeat in mid- to late-January. On greens, and in established fairways of perennial ryegrass that overseeded perennial ryegrass, a single preventive application are overseeded annually. There are two phases caused by this during the first half of December, or earlier if snow is expected, fungus: Pink Snow Mold and Microdochium Patch. Pink snow is optimal. Based on published reports, more consistent control mold phase occurs under snow cover and forms discrete, circular can be expected by tank-mixing iprodione and chlorothalonil patches (up to 12 inches in diameter) that can coalesce into large than by applying either fungicide alone. Avoid using high rates of - areas of blighted turf; and the Microdochium patch phase devel PCNB on putting greens after January 1st because of the potential ops in the absence of snow during cool, rainy weather as small, for occasional phytotoxicity to creeping bentgrass and annual water-soaked spots (typically 1-3 inches in diameter, occasionally bluegrass, especially if temperatures unexpectedly become warm expanding up to 8 inches) that often appear as “streaks.” Damage during the spring. Of the two grasses, creeping bentgrass is the associated with Microdochium patch often appears “smeared” more sensitive to PCNB phytotoxicity. Phytotoxicity from PCNB and may follow mower or drainage patterns. To suppress both ° F (21 ° is most likely when temperatures exceed 70 - C). PCNB ap types, mow turf until dormancy to avoid excess growth in autumn Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most * experiments; = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 21

22 (continued) 14. Pink Snow Mold/Microdochium Patch (= Fusarium Patch) 14. Pink Snow Mold/Microdochium Patch a a tions (x) tions (x) Efficacy* FRAC Efficacy* FRAC Interval Interval Code Code (days) or (days) or Applica- Applica- (continued) Some Trade Names Combination Products Fungicide: 14-28 11 Heritage azoxystrobin: 2.5 Contend A Once, late benzovinduiflupyr + difenoconazole: L 7 + 3 fall chlorothalonil: M5 21-28 2.5 Daconil Ultrex, Manicure, Concorde SST, Chlorostar, Echo L 14-28 boscalid + pyraclostrobin: Honor Intrinsic 7 + 11 1-2x Rubigan fenarimol: 3 2 M5 + P1 chlorothalonil + acibenzolar-S-methyl: 21-28 L Daconil Action 1-2x L 29 Secure fluazinam: M5 + 12 chlorothalonil + fludioxonil + propiconazole: 14-28 3 1x fludioxonil: Medallion 12 4 Instrata + 3 14-28 4 11 Fame fluoxastrobin: 4 M5 + 2 + chlorothalonil + iprodione + thiophanate- 28 Xzemplar 7 L 14-28 fluxapyroxad: Enclave 1 + 3 methyl + tebuconazole: hydrogen dioxide: Zerotol NC 7 L 3 chlorothalonil + propiconazole: M5 + 3 1-2X @ Concert, Variable iprodione: 2 3 Chipco 26GT, Andersons Fungicide X, Concert II 14-28 Raven, Lesco 18 Plus, Iprodione Pro chlorothalonil + tebuconazole: E-Scape ETQ 28 L M5 + 3 14-42 M3 Fore, Protect T/O, Mancozeb, Dithane mancozeb: 2 chlorothalonil + thiophanate-methyl: M5 + 1 3.5 14 ConSyst, 1-2x 3.5 metconazole: Tourney 3 Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C b NC mineral oil: Civitas 14-21 1 copper hydroxide + mancozeb: M1 + M3 L 7-14 Junction myclobutanil: Eagle 3 2 1-2x fluopyram + trifloxystrobin: 10-28 3 7+11 Exteris Stressgard PCNB: 1x 3.5 14 PCNB, Penstar, Terraclor, Turfcide, Revere 28 Fame C 11 + M5 4 fluoxastrobin + chlorothalonil: 7-14 polyoxin D: 19 3.5 Affirm Disarm M 11 + 3 L 14-28 fluoxastrobin + myclobutanil: propiconazole: 3 1x 3 Banner Maxx, Spectator, Savvi fluoxastrobin + tebuconazole: 21-30 Fame+T 11 + 3 3.5 14-28 3 pyraclostrobin: Insignia Intrinsic 11 3.5 Chipco 26GT + 1-2x @21- iprodione + chlorothalonil: 2 + M5 Reynoutria sachalinensis: Regalia PTO NC L 7-14 Daconil Ultrex, Pegasus L, E-Pro ETQ 28 tebuconazole: Torque, Mirage Stressgard, 3 L 10-14 2 + 1 L iprodione + thiophanate-methyl: 14-21 26/36, Sipcam Clearscape ETQ, Offset, ArmorTech Dovetail, Twosome, ArmorTech TMI TEB360 Interface Stressgard 2 + 11 iprodione + trifloxystrobin: 3.5 14-21 3 1 3336 EG, Fungo, Systec thiophanate-methyl: 1-2x 3.5 iprodione + trifloxystrobin + tebuconazole: 2 + 11 + 3 1x 1998, Cavalier, T-Storm Interface Stressgard + Mirage 2x thiram: Spotrete, Defiant M3 L 1 x (2 + 11) + 3.5 iprodione + trifloxystrobin + triadimefon: 60-90 2 3 Bayleton triadimefon: Interface Stressgard + Tartan (11 + 3) 3.5 trifloxystrobin: Compass 11 1-2x c 28 14+3 Oreon PCNB + tebuconazole: L triticonazole: Trinity, Triton 3 3.5 14-28 Lexicon 11 + 7 3 14-28 pyraclostrobin + fluxapyroxad: 2 vinclozolin: Curalan, Touché, Vorlan 2 10-21 1x pyraclostrobin + triticonazole: Pillar 11 + 3 3.5 Combination Products L 14-21 1 + 7 SysStar thiophanate-methyl + flutolanil: azoxystrobin + acibenzolar-S-methyl: L 11 + P1 Heritage 10-28 1x 11 + 3 Armada, Tartan trifloxystrobin + triadimefon: 4 Action a NC = Not classified. 14-21 azoxystrobin + chlorothalonil: Renown 11 + M5 L b To reduce the potential for phytotoxicity, do not apply during hot weather L azoxystrobin + difenoconazole: Briskway 11 + 3 14-28 (> 90°F) or periods of severe environmental stress, and do not combine azoxystrobin + propiconazole: Headway, 14-28, 11 + 3 3.5 with chlorothalonil, DMI fungicides, or iron-containing products under high temperatures and high humidity, or tank-mix with PCNB. Goliath WP, Contend B Contend B c Do not apply to cool-season turf at daytime temperatures of 85°F or higher. once Combine with a pigment to mask chlorosis that may occur at high label rate. ArmorTech azoxystrobin + tebuconazole: L 11 + 3 14-21 After application, immediately irrigate with 1/4 inch water. ZOXY-T, StrobeT plied at high rates to creeping bentgrass or annual bluegrass in annual bluegrass. High rates of Instrata or DMI fungicides alone late-autumn or early-winter can cause turf yellowing at spring can induce slight phytotoxicity (expressed as a foliar tip necrosis) that typically disappears with a return to regular mowing in the - greenup. Under sustained overcast, cool, rainy conditions, re peated applications of Civitas + Harmonizer haves induced some spring. Recovery from a disease outbreak can be hastened with phytotoxicity on annual bluegrass. A three-way mixture of Civitas light fertilization and by verticutting. + Harmonizer + Instrata has also been observed to cause injury on * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 experiments; = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 22

23 15. Powdery Mildew Blumeria graminis (Erysiphe graminis) Pathogen: [ blue- gram -ia ] [ Pronunciation: -innis ] mare [ airy- si -fee ] [ gram -innis ] Principal host: Kentucky bluegrass Season: April-November Confined mainly to shady areas. Avoid high nitrogen fertility. Renovate affected areas with more shade-tolerant tall fescues. (continued) 15. Powdery Mildew 15. Powdery Mildew a a tions (x) tions (x) FRAC Efficacy* Efficacy* FRAC Interval Interval Code Code (days) or (days) or Applica- Applica- Some Trade Names Combination Products (continued) Fungicide: azoxystrobin: 14-28 L 11 Heritage 11 + 3 azoxystrobin + propiconazole: 14-28 L Headway, 7-10 L NC Rhapsody Bacillus subtilis, strain QST 713: Goliath fenarimol: Rubigan 3 L 1x azoxystrobin + tebuconazole: 14-21 11 + 3 L ArmorTech ZOXY-T, StrobeT fluoxastrobin: L 11 Fame 14-28 b L 14-28 7 + 11 Honor Intrinsic boscalid + pyraclostrobin: Civitas 14 NC mineral oil: L chlorothalonil + propiconazole: Concert, M5 + 3 L 14-28 14-28 4 3 myclobutanil: Eagle Concert II Velista penthiopyrad: L 7 14 L chlorothalonil + tebuconazole: E-Scape ETQ M5 + 3 28 potassium dihydrogen phosphate: Nutrol NC L 7-14 M5 +1 14 L ConSyst, chlorothalonil + thiophanate-methyl: 14-28 3 4 Banner Maxx, Spectator, Savvi propiconazole: Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C Insignia Intrinsic 14-28 11 pyraclostrobin: L L Junction M1 + M3 7-14 copper hydroxide + mancozeb: L Reynoutria sachalinensis: 7-14 NC Regalia PTO 14-28 L 11 + M5 Fame C fluoxastrobin + chlorothalonil: 3 L tebuconazole: 28 Torque, Sipcam Clearscape ETQ, 14-28 L 11 + 3 Disarm M fluoxastrobin + myclobutanil: Offset, ArmorTech TEB360 L pyraclostrobin + fluxapyroxad: Lexicon 11 + 7 14-28 15-30 triadimefon: 3 4 Bayleton pyraclostrobin + triticonazole: L 11 + 3 14-28 Pillar Combination Products a NC = Not classified. L 14-28 11 + P1 azoxystrobin + acibenzolar-S-methyl: b To reduce the potential for phytotoxicity, do not apply during hot weather Heritage Action (> 90°F) or periods of severe environmental stress, and do not combine 14-21 azoxystrobin + chlorothalonil: Renown 11 + M5 L with chlorothalonil, DMI fungicides, or iron-containing products under L 14-28 11 + 3 Briskway azoxystrobin + difenoconazole: high temperatures and high humidity, or tank-mix with PCNB. should be applied to plant surfaces and not syringed after ap - (Cottony Blight) 16. Pythium Blight plication since they may undergo chemical changes in the soil Pythium species, especially Pathogen: P. aphanidermatum that reduce effectiveness. Avoid excessive use of mefenoxam P. graminicola and fan -idder- may Pronunciation: [ pith ium ] [ a- tum ] Pythium or metalaxyl, since resistance to these fungicides in pith [ ium ] [ gramma- -ola ] nick has been documented on perennial ryegrass aphanidermatum Principal hosts: Perennial ryegrass, creeping bentgrass, annual fairways on several Kentucky golf courses and other states. An bluegrass, tall fescue, fine fescue I fungicides was isolate of P. aphanidermatum resistant to Q Season: June-September o found in turfgrass in Iowa, and isolates resistant to propamocarb Favored by hot, wet, muggy weather and is especially active have been found in ornamentals, suggesting there is a significant ° C) and lows exceed 70 ° F (21 ° C) when highs exceed 90 ° F (32 resistance risk of resistance in this turfgrass pathogen. Use seed for at least two to three consecutive days. Avoid excessive soil treated with mefenoxam or metalaxyl, especially for seedings moisture and nitrogen fertility, water early in the day to allow made prior to early September. This seed treatment should be drying before nightfall, and improve drainage and air circula - sufficient to protect Kentucky bluegrass, tall fescue, and fine tion. Avoid mowing wet grass if active mycelium is present on fescues; for perennial ryegrass, a follow-up granular or spray diseased grass, which can spread spores of the disease. Short application may be necessary if weather permits disease activity. spray intervals (7-10 days) are sometimes needed under high For creeping bentgrass, the seed of which is normally not treated disease pressure, even for the most effective products. For with fungicide, treat the soil at seeding or shortly thereafter with curative situations, research suggests that cyazofamid, mefan - a systemic like cyazofamid, mefenoxam, or propamocarb; repeat oxam, and propamocarb are the most efficacious. Tank-mixes at least once post-emergence if the seeding was made in August. of mancozeb and chloroneb may provide poorer control than Flutolanil and azoxystrobin, when applied for control of brown each fungicide used alone. When using fosetyl-Al, research patch, have both been shown to substantially increase Pythium suggests that two or more consecutive applications of this blight activity if conditions favor Pythium. Koban (ethazole) fungicide are necessary for good control under severe disease may cause phytotoxicity if the application is made during hot pressure; fosetyl-Al often provides poor curative control of weather, especially in low spray gallonage; see label directions Pythium. Phosphite (phosphonate) materials like fosetyl-Al and restrictions. * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most 1 = no N = control is inconsistent between experiments but performs well in some instances; experiments; = fair to good control in most experiments; 2 = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 23

24 (continued) 16. Pythium Blight 16. Pythium Blight (Cottony Blight) a a Efficacy* FRAC Efficacy* FRAC Interval Interval Code Code (days) (days) Combination Products Some Trade Names (continued) Fungicide: azoxystrobin: 10-14 3 11 Heritage Headway, Goliath 11 + 3 L 14 azoxystrobin + propiconazole: 5-7 Terraneb SP, Andersons Fungicide V 14 chloroneb: L 10-21 azoxystrobin + tebuconazole: ArmorTech ZOXY-T, 11 + 3 L StrobeT 3.5 14-21 21 Segway cyazofamid: Honor Intrinsic 7 + 11 boscalid + pyraclostrobin: 10-14 L Koban, Terrazole ethazole (= etridiazole): 14 1 5-10 7-14 L copper hydroxide + mancozeb: Junction M1 + M3 Fame 11 2.5 7-14 fluoxastrobin: 2 43 + 28 Stellar fluopicolide + propamocarb: 14 33 Chipco Signature, Signature Xtra Stressgard, 3 14-21 fosetyl-Al: Prodigy fluoxastrobin + chlorothalonil: Fame C 11 + M5 L 7-14 5 2 M3 Fore, Protect T/O, Mancozeb, Dithane mancozeb: fluoxastrobin + myclobutanil: Disarm M 11 + 3 L 14 b Subdue MAXX, Quell, Fenox mefenoxam: 7-21 4 fluoxastrobin + tebuconazole: Fame+T 11 + 3 L 21 3 b L 33 + M5 Vitalonil potassium phosphite + chlorothalonil: 7-14 7-21 metalaxyl: 4 Subdue 2E, Andersons Pythium Control 2.5 pyraclostrobin + fluxapyroxad: 14 11 + 7 Lexicon L phosphite (salts of phosphorous acid): 33 14 Appear, Alude, 2.0 to c Biophos, Fiata Stressgard, Magellan, Resyst, Vital 2.5 pyraclostrobin + triticonazole: Pillar L 14 11 + 3 Banol propamocarb: 7-21 3.0 28 L Reynoutria sachalinensis: Regalia PTO 7-14 NC Insignia Intrinsic pyraclostrobin: 11 2.5 10-14 a NC = Not classified b Isolates of Pythium species resistant to mefenoxam and metalaxyl have Combination Products been reported in some locations. Heritage azoxystrobin + acibenzolar-S-methyl: L 11 + P1 10-14 c Efficacy varies somewhat among formulated products. Action 17. Pythium Root Dysfunction 17. Pythium Root Dysfunction possibly other Pathogen: Principally Pythium volutum, a Pythium spp. tum ] Pronunciation: ium ] [ va- pith [ loo FRAC Efficacy* Interval Code (days) Fungicide: Some Trade Names Principal hosts: Creeping bentgrass,annual bluegrass b 10-14 azoxystrobin: Heritage 11 2 21 cyazofamid: Segway 3 14-21 This disease is often associated with stands less than eight years Koban 14 1 5-10 ethazole: old, on high-sand-content greens. In Kentucky, this disease has fluoxastrobin: Fame 11 L 14-28 sometimes been associated with the following circumstances: fosetyl-Al: 33 1 14-21 Chipco Signature established soil-based greens overlain with several inches of sand mefenoxam: 4 10-21 1.5 Quell 33 L 7-14 phosphite (salts of phosphorous acid): Appear topdressing or newly established, sand-based creeping bentgrass propamocarb: Banol 28 1.5 7-21 greens, especially during the first autumn. Symptoms generally 14-28 3 pyraclostrobin: Insignia Intrinsic 11 occur during late-spring (with symptoms progressing through L NC Trichoderma harzianum Rifai T-22 plus 30 the heat of summer) or during mid- to late-autumn. Symptoms Trichoderma virens G14: TurfShield PLUS often develop first on mounds or sloped areas, particularly if re - Combination Products Heritage 11 + P1 L 21-28 azoxystrobin + acibenzolar-S-methyl: ceiving full sun. Root infections develop most aggressively at soil Action ° F (12 -24 temperatures between 54-75 ° C), although symptoms 21-28 L 11 + 3 azoxystrobin + propiconazole: Headway, Goliath may develop a month or more later, during hot weather. L boscalid + pyraclostrobin: Honor Intrinsic 7 + 11 14-28 14-28 fluoxastrobin + chlorothalonil: Fame C 11 + M5 L Maintain adequate nitrogen fertility, as this disease is most 14-28 L 11 + 7 pyraclostrobin + fluxapyroxad: Lexicon common in nitrogen-deficient turfgrass. If the soil profile shows pyraclostrobin + triticonazole: Pillar 11 + 3 L 14 signs of layering, aerify as needed. A soil horizon with excessive a NC = Not classified. b organic-matter accumulation in the root zone of a sand-based Based on a manufacturer 2(ee) recommendation. green can hold excessive moisture and favor infection. If this condition exists, aerify in spring or autumn with 0.25-inch to height above 0.125 inch during summer and reduce mowing 0.50-inch tines on close spacing (1.25 inches to 1.5 inches) just frequency. Rolling greens daily and mowing every other day may deeply enough to penetrate the organic layer, then back-fill holes reduce the disease severity and improve the tolerance of the turf with sand; during the summer, punch holes in the layer with solid to infection. Consider using a walk-behind mower. Soil surfac - tines and lightly topdress to maintain adequate gas exchange. tants may improve uniformity of water penetration into the root If heavy organic matter is in the top inch, deep verticutting in zone, thus assisting with irrigation management. During an active spring or autumn will remove organic matter more effectively outbreak, avoid mowing when wet to reduce mechanical damage than aerification but will require longer recovery times, so this to infected grass. Overseed as soon as possible after an outbreak, practice should be used only when good growing conditions but be sure to avoid use of mancozeb prior to overseeding, since prevail. During periods when soil temperatures at a 2-inch depth that material is phytotoxic to seedlings of various grasses. are between 54-75 ° F (12 -24 ° C), avoid overly frequent irrigations. Fungicides will be more effective if used preventively rather However, once symptoms develop, hand-watering severely af - than curatively. On sites with a history of disease, treat preven - fected areas can help affected turf remain alive. Increase mowing tively every 21-28 days when soil temperatures at a 2-inch depth Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most * experiments; = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 24

25 ° C), the temperature range under ° are between 54-75 F (12 -24 y Insignia 20WG (0.9 oz/1,000 sq ft, watered in with 0.125 inch which P. volutum is most active. Except as noted below, sprayed of irrigation). fungicides should be applied in at least 4-6 gal of water/1,000 Segway 3.3SC (0.9 fl oz/1,000 sq ft, watered in with 0.125 y sq ft or followed immediately with 0.125 inch of irrigation to inch of irrigation). wash fungicide into the root zone. Granulars should be applied Signature 80WG + Banol 6SC (4 oz + 2 fl oz/1,000 sq ft) or y when the turf is dry and watered in after application. Koban Signature 80WG + Subdue Maxx 1ME (4 oz + 1 fl oz/1,000 may cause phytotoxicity if the application is made during hot sq ft) applied in 2 gal/1,000 sq ft and left on the foliage. weather, especially in low spray gallonage; see label directions This program can be used preventively every 21-28 days in and restrictions. In addition to the individual products listed the autumn and spring when soil temperatures are 54-75 F ° in the accompanying table, tank-mixes of Signature 80WG C). This program can also be used curatively every 14- ° (12 -24 + Banol 6SC (4 oz + 2 fl oz/1,000 sq ft) or Signature 80WG + 28 days. If spraying fungicides curatively, an increased mowing Subdue Maxx 2ME (4 oz + 1 fl oz/1,000 sq ft) also reportedly height and appropriate nitrogen fertilization are necessary to have provided good disease suppression. These tank-mixes are allow turf recovery. Since pyraclostrobin and cyazofamid are at reportedly most effective when applied to the foliage in 2 gal of risk for development of resistance, be sure to rotate fungicides water/1,000 sq ft. according to the program described above. The spray program recommended by North Carolina State Application of Segway 3.3SC resulted in increased brown University researchers (who have published the most extensive patch damage in one creeping bentgrass putting green test. research base on this disease) is as follows: Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most * experiments; = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 25

26 pyraclostrobin, and vinclozolin. In one test, a formulation of 18. Red Thread myclobutanil (Eagle) caused foliar discoloration and stand Laetisaria fuciformis (Corticium fuciforme) Pathogen: thinning to creeping red fescue when applied for red thread mis ] sar [ layta- Pronunciation: ia ] [ fewsi- for m-a ] [ cor- tiss ium ] [ fewsi- for control. A related disease called Pink Patch ( Limonomyces Principal hosts: Perennial ryegrass, fine-leaf fescues, tall fescue, ) occasionally develops during humid, mild weather roseipellis Kentucky bluegrass in winter on creeping bentgrass and on dormant bermudagrass. Season: February-November Treatment against pink patch is not recommended in most - Maintain adequate nitrogen fertility. In several tests, azoxys circumstances. However, if considering use of a fungicide, be trobin has provided good curative performance. A recent aware that testing indicates that flutolanil is ineffective against field study also showed excellent curative recovery from an pink patch. Fungicides with the greatest activity against pink application of 1 lb urea/1,000 sq ft, without application of patch include azoxystrobin, fenarimol, iprodione, mancozeb, fungicide. In that same test, good curative recovery was also myclobutanil, propiconazole, and thiophanate-methyl. observed with chlorothalonil, flutolanil, iprodione, mancozeb, (continued) 18. Red Thread 18. Red Thread a a FRAC Efficacy* FRAC Efficacy* Interval Interval Code Code (days) (days) Fungicide: Some Trade Names (continued) Combined Products azoxystrobin: 14-28 Heritage 11 4 boscalid + pyraclostrobin: 14-28 L 7 + 11 Honor Intrinsic 3 chlorothalonil: Daconil Ultrex, Manicure, Concorde M5 7-10 chlorothalonil + acibenzolar-S-methyl: L 7-14 M5 + P1 Daconil SST, Chlorostar, Echo, Pegasus L Action 3 2 30 fenarimol: Rubigan M5 + 12 L 14-21 chlorothalonil + fludioxonil + propiconazole: Instrata + 3 29 L fluazinam: Secure 14 E-Pro ETQ, Chipco 26GT 14 L M5 + 2 chlorothalonil + iprodione: fluoxastrobin: 14-28 11 Fame L + Daconil Ultrex 21-28 Prostar flutolanil: 7 4 14-28 chlorothalonil + iprodione + thiophanate-methyl M5 + 2 + L iprodione: 14 Chipco 26GT, Raven, Lesco 18 Plus, 3.5 2 + tebuconazole: 1 + 3 Enclave Iprodione Pro 14-21 Concert, Concert II chlorothalonil + propiconazole: L M5 + 3 7-14 Fore, Protect T/O, Mancozeb, Dithane mancozeb: M3 2 E-Scape ETQ chlorothalonil + tebuconazole: 28 L M5 + 3 metconazole: Tourney 3 L 14 b ConSyst, 14 L M5 + 1 chlorothalonil + thiophanate-methyl: mineral oil: Civitas NC 14 L Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C 14-21 myclobutanil: Eagle 3 2 Junction M1 + M3 L 7-14 copper hydroxide + mancozeb: penthiopyrad: 7 Velista 14 4 L 7+11 14-28 Exteris Stressgard fluopyram + trifloxystrobin: 4 7-14 polyoxin D: 19 Affirm fluoxastrobin + chlorothalonil: L 11 + M5 Fame C 14-28 14-21 propiconazole: Banner Maxx, Spectator, Savvi 3 3 14-28 L Disarm M fluoxastrobin + myclobutanil: 11 + 3 pyraclostrobin: Insignia Intrinsic 11 14-28 4 L 11 + 3 Fame+T fluoxastrobin + tebuconazole: 21-28 NC Reynoutria sachalinensis: Regalia PTO L 7-14 iprodione + thiophanate-methyl: 2 + 1 26/36, Dovetail, L 14-21 tebuconazole: Torque, Mirage Stressgard, Sipcam 14-28 3 L Twosome, ArmorTech TMI Clearscape ETQ, Offset, ArmorTech TEB360 L iprodione + trifloxystrobin: Interface Stressgard 14 2 + 11 7-14 thiophanate-methyl: 1 3336 EG, Fungo, Systec 1998, 1 c Oreon 14-28 14+3 PCNB + tebuconazole: L Cavalier, T-Storm potassium phosphite + chlorothalonil: Vitalonil 33 + M5 7-10 L 3 3 15-30 Bayleton triadimefon: pyraclostrobin + fluxapyroxad: Lexicon 11 + 7 L 14-28 trifloxystrobin: L 14-21 Compass 11 L 14-28 11 + 3 Pillar pyraclostrobin + triticonazole: triticonazole: 14-28 4 3 Trinity, Triton SysStar L thiophanate-methyl + flutolanil: 14-28 1 + 7 vinclozolin: 14-28 2 2 Curalan, Touché, Vorlan trifloxystrobin + triadimefon: 3 Armada, Tartan 14-28 11 + 3 Combination Products a NC = Not classified. L azoxystrobin + acibenzolar-S-methyl: 11 + P1 14-28 Heritage b To reduce the potential for phytotoxicity, do not apply during hot weather Action (> 90°F) or periods of severe environmental stress, and do not combine Renown azoxystrobin + chlorothalonil: L 11 + M5 14-21 with chlorothalonil, DMI fungicides, or iron-containing products under 14-28 L 11 + 3 azoxystrobin + difenoconazole: Briskway high temperatures and high humidity, or tank-mix with PCNB. c azoxystrobin + propiconazole: Headway, Goliath 11 + 3 L 14-28 Do not apply to cool-season turf at daytime temperatures of 85°F or higher. Combine with a pigment to mask chlorosis that may occur at high label rate. 14-21 ArmorTech ZOXY-T, azoxystrobin + tebuconazole: 11 + 3 L After application, immediately irrigate with 1/4 inch water. StrobeT Maintain adequate fertility, especially nitrogen and potash. A (previously 19. Rhizoctonia Leaf and Sheath Spot weekly application of 0.25 lb N/1,000 sq ft is advisable for at-risk considered a variant of Brown Patch) greens. Manage thatch appropriately. Raise the height of cut Chrysorhiza zeae (Rhizoctonia zeae) Pathogen: prior to and during periods of stress, and incorporate rolling if -ee ] zee ri [ crisso- Pronunciation: za ] [ -ee ] zee -nia ] [ toe [ rizoc- added green speed is necessary. Aggressively verticut and aerify, Creeping bentgrass, roughstalk bluegrass Principal hosts: but only during times of year when the turf is actively growing. Season: June-August * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most N = control is inconsistent between experiments but performs well in some instances; 1 experiments; = fair to good control in most experiments; = no 2 = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 26

27 19. Rhizoctonia Leaf and Sheath Spot On several turf species, failures of fungicides that are normally effective against brown patch (e.g., thiophanate-methyl) may which can some Chrysorhiza zeae, - indicate the presence of times be active during very hot conditions (sustained period FRAC Efficacy* Interval Code (days) Fungicide: Some Trade Names of high temperatures in the 90s). Avoid thiophanate-methyl as 14-28 L azoxystrobin: Heritage TL 11 Daconil Ultrex, Echo, Ensign, Equus, chlorothalonil: 7-14 L M5 a stand-alone fungicide during hot weather. Syringe fungicides Mainsail before they dry to move them into the crown. Some studies polyoxin D: Affirm 19 L 7-14 also indicate that dicarboximide fungicides (iprodione and pyraclostrobin: 14-28 11 L Insignia Intrinsic vinclozolin, FRAC group 2) have poor effectiveness and may Combination Products allow disease to develop when used as stand-alone fungicides azoxystrobin + acibenzolar-S-methyl: Heritage 11 + P1 L 14-28 Action during hot weather. Preventive fungicide applications provide 14-21 azoxystrobin + chlorothalonil: Renown 11 + M5 L best results; curative applications provide very erratic results. 11 + 3 14-28 Briskway L azoxystrobin + difenoconazole: Headway, Goliath 11 + 3 L 14-28 azoxystrobin + propiconazole: azoxystrobin + tebuconazole: ArmorTech ZOXY-T, 14-21 11 + 3 L StrobeT 14-28 Honor Intrinsic 7 + 11 L boscalid + pyraclostrobin: pyraclostrobin + fluxapyroxad: Lexicon 11 + 7 L 14-28 28 pyraclostrobin + triticonazole: Pillar 11 + 3 L Maintain adequate nitrogen fertility and soil moisture to 20. Rusts maintain turf growth. An application of nitrogen fertilizer can Pathogen: Puccinia coronata Puccinia graminis and - help a sward recover from a rust outbreak. Fungicides are com Pronunciation: na sin nia ] [ coro- ta ] [ puck- [ puck- gram nia ] [ sin -innis ] monly not necessary in actively growing turf under Kentucky Bluegrasses, perennial ryegrass, tall fescue, Principal hosts: conditions. See label for specific rust diseases controlled. zoysiagrass Season: August-November a (continued) 20. Rusts 20. Rusts b b FRAC Efficacy* Interval Code (days) FRAC Efficacy* Interval Combination Products (continued) Code (days) Fungicide: Some Trade Names Honor Intrinsic 14-28 7 + 11 L boscalid + pyraclostrobin: azoxystrobin: 4 14-28 11 Heritage M5 + P1 3 chlorothalonil + acibenzolar-S-methyl: Daconil 14 NC L Bacillus subtilis, strain QST 713: 7-10 Rhapsody Action M5 3 7-14 chlorothalonil: Daconil Ultrex, Manicure, Concorde L chlorothalonil + fludioxonil + propiconazole: M5 + 12 14-28 SST, Chlorostar, Echo, Pegasus L + 3 Instrata fluazinam: Secure L 14 29 M5 + 2 14 chlorothalonil + iprodione: E-Pro ETQ, Chipco 26GT L 14-28 11 fluoxastrobin: Fame L + Daconil Ultrex Fore, Manzate 200, Protect T/O, Dithane, mancozeb: 7-14 3 M3 14-28 chlorothalonil + propiconazole: Concert, Concert II M5 + 3 L Pentathlon L 28 E-Scape ETQ M5 + 3 chlorothalonil + tebuconazole: mandestrobin: 14 3 11 Pinpoint 14 L M5 + 1 ConSyst, chlorothalonil + thiophanate-methyl: 3.5 14 metconazole: 3 Tourney Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C c 14-21 NC Civitas mineral oil (Crown rust): L copper hydroxide + mancozeb: Junction M1 + M3 L 7-14 3 Eagle myclobutanil: 14-28 L fluopyram + trifloxystrobin: L 14-28 Exteris Stressgard 7+11 14 L penthiopyrad: Velista 7 Fame C L 14-28 11 + M5 fluoxastrobin + chlorothalonil: Banner Maxx, Spectator, Savvi 3 3.5 14-28 propiconazole: L 11 + 3 14-28 Disarm M fluoxastrobin + myclobutanil: 3 pyraclostrobin: Insignia Intrinsic 11 14-28 2 + 11 14-28 iprodione + trifloxystrobin: Interface Stressgard L NC 7-14 Regalia PTO Reynoutria sachalinensis: L d Oreon PCNB + tebuconazole: 14+3 14-28 L 14-28 L 3 tebuconazole: Torque, Mirage Stressgard, Sipcam 14-28 L 11 + 7 Lexicon pyraclostrobin + fluxapyroxad: Clearscape ETQ, Offset, ArmorTech TEB360 pyraclostrobin + triticonazole: 11 + 3 L 14-28 Pillar 7-14 2.5 1 3336 EG thiophanate-methyl: Armada, Tartan 3.5 14-28 trifloxystrobin + triadimefon: 11 + 3 14-30 3.5 3 Bayleton, Andersons Fungicide VII triadimefon: a 14-21 2.5 11 Compass trifloxystrobin: - Check label to assure product is labeled for the particular rust disease pres ent. triticonazole: Trinity, Triton 14-28 L 3 b NC = Not classified. c Combination Products To reduce the potential for phytotoxicity, do not apply during hot weather Heritage azoxystrobin + acibenzolar-S-methyl: 11 + P1 L 14-28 (> 90°F) or periods of severe environmental stress, and do not combine Action with chlorothalonil, DMI fungicides, or iron-containing products under high temperatures and high humidity, or tank-mix with PCNB. 11 + M5 L azoxystrobin + chlorothalonil: Renown 14-21 d - Do not apply to cool-season turf at daytime temperatures of 85°F or high L 11 + 3 Briskway azoxystrobin + difenoconazole: 14-28 er. Combine with a pigment to mask chlorosis that may occur at high label L azoxystrobin + propiconazole: Headway, Goliath 11 + 3 14-28 rate. After application, immediately irrigate with 1/4 inch water. L azoxystrobin + tebuconazole: ArmorTech ZOXY-T, 11 + 3 14-21 StrobeT * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most 2 N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; = no experiments; efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 27

28 21. Slime Molds and spp. Fuligo Physarum Pathogen: [ fie- Pronunciation: sah rum ] lee [ few- go ] Principal hosts: All turfgrasses May-October Season: No fungicide necessary. Fruiting structures can be removed by hosing leaves with water, mowing, poling, or brushing. Con - trol thatch. Fungicidal control of this disease can be very inconsistent; 22. Spring Dead Spot - golf course superintendents are encouraged to carefully evalu Ophiosphaerella herpotricha Pathogen: ate whether fungicidal control is the best course of action for Ophiosphaerella korrae and [ ofio-sfa- a ] [ her- rell Pronunciation: rick-a ] pat their situation. Research shows that applying only one spray core -ee ] a ] [ [ ofio-sfa- rell often provides no disease control and two to four sprays are Bermudagrass Principal hosts: necessary to achieve significant reductions in disease severity. April-July Season: Therefore, it is better to either spray several times or not use For best results, use cultural control practices over several fungicides. Two applications—one in late-August and another seasons, since effective management of this disease requires a in late-September (target soil temperatures at a 2-inch depth long-term approach that is designed to enhance the root system ° ° F [16 -2 7 of 60-80 C])—are usually the minimum needed in of bermudagrass. Avoid late-summer nitrogen fertilization; ap - Kentucky to achieve some control using fungicides although, ply the final nitrogen application no later than mid-July so that the turf runs low in nitrogen by mid-September. Raise mowing 22. Spring Dead Spot height before Labor Day. Minimize thatch and soil compaction, - since these impede root development. Maintain good soil drain a - age to allow roots to flourish. Maintain adequate potassium fer tility levels to enhance turf resistance to the disease. On putting tions (x) Efficacy* FRAC Interval Code (days) or Applica- Fungicide: Some Trade Names 2 azoxystrobin: Heritage 11 1-2x greens, avoid using topdressings with a pH above 6.0. Recent 3 1x fenarimol: Rubigan 2 research in North Carolina has shown that fertilization with fluoxastrobin: 11 L 14-28 Fame O. korrae, calcium nitrate helps suppress damage from whereas b Civitas NC Sept. and mineral oil: L O. herpotricha damage from is reduced by use of ammonium Oct. before dormancy sulfate. If using ammonium-based fertilizers, wash them off 2 Eagle myclobutanil: 1-2x 3 ° leaves if applied when temperatures will exceed 80 C) to F (27 ° c Velista 7 28 penthiopyrad: L avoid burn. If not using exclusively ammonium-based nitrogen Banner Maxx, Spectator, propiconazole: 1-3x 1.5 3 Savvi fertilizer, maintain the soil pH around 5.2 to 5.3 (extracted in tebuconazole: Torque, Mirage Stressgard, 3 3 2x @ 28 distilled water) by making light applications of flowers of sulfur Sipcam Clearscape ETQ, Offset, ArmorTech (2 lb/1,000 sq ft) to areas with the disease, evaluating the results TEB360 - for a year before re-treating. An incremental approach is recom Combination Products L 14-28 azoxystrobin + acibenzolar-S-methyl: 11 + P1 mended since overapplication of sulfur can result in slow spring Heritage Action greenup and temporary turf thinning, particularly in soils with a L azoxystrobin + propiconazole: Headway, 11 + 3 14-28 low organic-matter content. Following sulfur applications, most Goliath azoxystrobin + tebuconazole: 1-2x @ L 11 + 3 ArmorTech of the acidity may be confined to the top 0.5-1.0 inch of soil, so ZOXY-T, StrobeT 14-21 monitor the soil pH by sampling at this depth. For turf areas 14-28 chlorothalonil + iprodione + thiophanate- L M5 + 2 + where the disease has been particularly active, an aggressive Enclave 1 + 3 methyl + tebuconazole: chlorothalonil + tebuconazole: E-Scape ETQ M5 + 3 L 28 mid-summer aerification program has been shown to reduce Fame C L 14-28 fluoxastrobin + chlorothalonil: 11 + M5 disease pressure. For such areas, core-aerify (0.5-inch tines or Disarm M L 14-28 fluoxastrobin + myclobutanil: 11 + 3 less) and verticut (0.25-inch depth) in early-July and again in 11 + 3 L 21-28 fluoxastrobin + tebuconazole: Fame+T d - early-August, as long as soil moisture is adequate for turf re 14+3 PCNB + tebuconazole: 28 Oreon L a covery (but avoid vertical mowing after September 1). Football NC = Not classified b To reduce the potential for phytotoxicity, do not apply during hot weather fields should not be subjected to aggressive vertical mowing (> 90°F) or periods of severe environmental stress, and do not combine late in the summer, because this will unduly compromise sod with chlorothalonil, DMI fungicides, or iron-containing products under high temperatures and high humidity, or tank-mix with PCNB. strength. Dinitroaniline (DNA) pre-emergent herbicides (for c Labeled based on manufacturer-issued 2(ee) recommendation. d control of grassy annuals) may slow recovery of bermudagrass Do not apply to cool-season turf at daytime temperatures of 85°F or high - er. Combine with a pigment to mask chlorosis that may occur at high label from spring dead spot damage. rate. After application, immediately irrigate with 1/4 inch water. Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most * experiments; = no N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; 2 efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 28

29 even with these applications, control ranges from 35-90%. If order to minimize fungicide use against this disease, map areas - using a single application, apply in early-September. Light ir affected by the disease and treat only those areas. Research on fungicide applications at spring greenup indicates that these rigation immediately after application will sometimes improve applications provide no improvement in turfgrass recovery control, especially in spray volumes of 2 gal/1,000 sq ft or less. from disease. Applications of DMI fungicides (FRAC Code 3) The benefit of immediate irrigation may be minimal under light may delay recovery by causing phytotoxicity, as summertime disease pressure, but there is little harm in implementing the practice. While disease control may be incomplete, sometimes applications of certain DMI fungicides (specifically, products - containing metconazole, propiconazole, tebuconazole, triad fungicides improve survival enough to allow rapid regrowth into affected patches. In one test, propiconazole was reported imefon, or triticonazole) have been shown to cause phytotoxicity (sou rce=PDM R 8:T010). to increase susceptibility to frost and delay spring greenup. In reduce pH but more slowly. Wash ammonium sulfate off leaves (Poa Patch) 23. Summer Patch F (27 ° if applied when temperatures will exceed 80 ° C) to avoid Magnaporthiopsis poae Pathogen: burn. Avoid nitrate-based fertilizers, which can raise soil pH -ee ] poe thy opsis ] [ por [ magna- Pronunciation: and enhance symptoms. At symptom onset, an application of Principal hosts: Kentucky bluegrass, annual bluegrass, fine fescues 0.2 lb of nitrogen as ammonium sulfate in 20 gal of water/1,000 Season: July-September sq ft can help promote recovery, although the benefit is partial Raise mowing height and irrigate deeply and infrequently dur - and temporary (2-3 weeks in some research trials). Renovate ing mid- to late-summer. Light, frequent irrigation during the with resistant varieties of Kentucky bluegrass or with perennial heat of summer favors continued disease development, resulting ryegrass or tall fescue. Root infections are most aggressive when in greater root rot than that which results with a deep, infre - the soil is warm, saturated, and compacted. Therefore, aerify quent irrigation program. Use acidifying fertilizers as nitrogen with hollow tines (when symptoms are not present) to reduce sources, or use sulfur applications, both of which will lower soil compaction and improve oxygenation of the soil profile. Recent pH; however, calcareous soils or frequent irrigation of the turf research at the University of Connecticut has shown that solid - with high pH water will counteract this effect. The most acidify tines can enhance disease severity, presumably by increasing ing fertilizer is ammonium sulfate; sulfur-coated urea will also compaction at the bottom of the coring holes (similar to a plow 23. Summer Patch 23. Summer Patch (Poa Patch) (continued) a a tions (x) tions (x) FRAC Efficacy* Efficacy* FRAC Interval Interval Code Code (days) or (days) or Applica- Applica- Fungicide: Some Trade Names Combination Products (continued) Honor Intrinsic boscalid + pyraclostrobin: 7 + 11 14-28 3 azoxystrobin: 14-28 3.5 11 Heritage 14-28 L M5 + 12 chlorothalonil + fludioxonil + propiconazole: fenarimol: 3 2 Rubigan 1-2x Instrata + 3 fludioxonil: 12 14 Medallion L chlorothalonil + iprodione: E-Pro ETQ, Chipco M5 + 2 L 28 14-28 11 Fame fluoxastrobin: 3.5 26GT + Daconil Ultrex Xzemplar 14-28 fluxapyroxad: 7 2.5 L M5 + 2 + 14-28 chlorothalonil + iprodione + thiophanate- 7 hydrogen dioxide: Zerotol L NC Enclave 1 + 3 methyl + tebuconazole: 14 metconazole: 3 3 Tourney M5 + 3 L 14 chlorothalonil + propiconazole: Concert, b Civitas mineral oil: 7 NC L Concert II myclobutanil: 28 3 3 Eagle chlorothalonil + tebuconazole: E-Scape ETQ M5 + 3 L 28 c 14-28 penthiopyrad: Velista 7 2.5 14 M5 + 1 ConSyst, L chlorothalonil + thiophanate-methyl: Banner Maxx, Spectator, Savvi 14-28 3 3 propiconazole: Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C pyraclostrobin: 11 3.5 14-28 Insignia Intrinsic L 11 + M5 Fame C fluoxastrobin + chlorothalonil: 14-28 3 14-28 3 tebuconazole: Torque, Mirage Stressgard, Disarm M 11 + 3 L fluoxastrobin + myclobutanil: 14-28 Sipcam Clearscape ETQ, Offset, ArmorTech L 21-28 fluoxastrobin + tebuconazole: 11 + 3 Fame+T TEB360 d PCNB + tebuconazole: 14-28 Oreon 14+3 L 3336 EG, Fungo, Systec thiophanate-methyl: 10-21 2.5 1 3.5 14-28 11 + 7 Lexicon pyraclostrobin + fluxapyroxad: 1998, Cavalier, T-Storm 11 + 3 28 3.5 pyraclostrobin + triticonazole: Pillar 3 triadimefon: 3 30 Bayleton trifloxystrobin + triadimefon: Armada, Tartan 3 1-3x @ 11 + 3 21-28 trifloxystrobin: Compass 11 3 21-28 14-28 triticonazole: 3 3 Trinity, Triton a NC = Not classified. Combination Products b To reduce the potential for phytotoxicity, do not apply during hot weather azoxystrobin + acibenzolar-S-methyl: 11 + P1 Heritage 14-28 3 (> 90°F) or periods of severe environmental stress, and do not combine Action with chlorothalonil, DMI fungicides, or iron-containing products under 11 + 3 3.5 14-28 azoxystrobin + difenoconazole: Briskway high temperatures and high humidity, or tank-mix with PCNB. c Labeled based on manufacturer-issued 2(ee) recommendation. 3.5 14-28 Headway, azoxystrobin + propiconazole: 11 + 3 d Do not apply to cool-season turf at daytime temperatures of 85°F or high - Goliath er. Combine with a pigment to mask chlorosis that may occur at high label rate. After application, immediately irrigate with 1/4 inch water. * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most 2 N = control is inconsistent between experiments but performs well in some instances; 1 = fair to good control in most experiments; = no experiments; efficacy; L = limited published data on effectiveness; + = intermediate between two efficacy categories. 29

30 regulators mefluidide (Embark) and flurprimidol (Cutless) have layer). Alternate aerification depth periodically to avoid this - been shown to enhance symptoms of summer patch. Greater ef problem. Once annually, apply manganese sulfate at a rate of fectiveness using fungicides on putting greens may be achieved by 2 lb Mn/acre in the spring. Preventive fungicide applications including a foliar “spoon-feeding” program of 0.25-0.5 lb N/1,000 from May-August are more effective than curative treatments. sq ft monthly from June through August. Putting greens with significant annual bluegrass infestations and a previous history of disease will require preventive treat For curative treatments, studies suggest that propiconazole, - ment against summer patch. Begin preventive applications in late- - azoxystrobin, and myclobutanil are preferred choices. Thio April to mid-May, depending on how early soils warm up. Begin phanate-methyl has provided inconsistent control as a curative treatment, and triadimefon has shown good efficacy only in a preventive treatments when soil temperature at a 2-inch depth preventive use. If spraying, control may sometimes be improved in mid-afternoon is at least 65 C) for five to six consecutive F (18 ° ° by applying fungicides (particularly thiophanate-methyl) in at days. Apply DMI fungicides at summer patch rates no later than least 5 gal of water/1,000 sq ft or by washing fungicides into - early-June to minimize the risk of excessive turf growth regula tion and phytotoxicity. Avoid using topdressings with a pH above the root zone before they dry with 0.1-0.125 inch of irrigation. If applying granulars, apply when the turf is dry, then irrigate 6.0. Also avoid growth regulators containing paclobutrazole or into the thatch. Avoid repeated use of chlorothalonil or iprodi flurprimidol while high rates of DMI fungicides are in place to - further minimize phytotoxicity, especially during the months of one during mid- to late-summer, as they have been associated June through August, when hot weather can develop. Research with enhanced symptom development from summer patch in has shown that putting-green turf exhibiting growth-regulating certain tests. Torque caused phytotoxicity (yellowing, thinning) on annual bluegrass in several published tests. effects of DMI fungicides can suffer significantly greater infesta - tions of algae in summer due to reduced turf density. The growth 24. Take-All Patch (Ophiobolus Patch) (Ophiobolus Patch) 24. Take-All Patch Pathogen: Gaeumannomyces graminis var. avenae a [ goy- no- man Pronunciation: -innis ] gram my seas ] [ -nee ] vee [ ah- tions (x) Efficacy* FRAC Interval Code (days) or Applica- e: Fungicid Some Trade Names Principal hosts: Creeping bentgrass 3.5 11 2-4x azoxystrobin: Heritage April-October, especially April-July Season: 2.5 2x Rubigan fenarimol: 3 Fame fluoxastrobin: 11 L 28 Often most severe in new greens, especially when lime has 7 L NC Zerotol hydrogen dioxide: been incorporated into the root zone. Avoid using topdressings 14 mandestrobin: Pinpoint 11 L with a pH above 6.0, which can enhance symptoms. Maintain 3 14 metconazole: Tourney L propiconazole: Banner Maxx, Spectator, Savvi 2-4x 2.5 3 adequate levels of potassium and phosphorous. Reduce thatch, 28 3 11 Insignia Intrinsic pyraclostrobin: and aerify (but curtail these activities if symptoms are present Reynoutria sachalinensis: 7-14 L NC Regalia PTO to avoid excessive stress on the grass). Maintain soil pH between tebuconazole: Torque, Mirage Stressgard, 3 L 1-2x @ 5.5 and 6.0. Use ammonium sulfate during spring and autumn. Sipcam Clearscape ETQ, Offset, ArmorTech 14-28 TEB360 - Substitute another nitrogen source with less burn potential dur thiophanate-methyl: 1 14 3336 EG, Fungo, Systec 1.5 ing summer, but minimize the use of nitrate forms of nitrogen, 1998, Cavalier, T-Storm since they can raise soil pH and enhance the disease. Wash am - 2-4x 2.5 3 Bayleton triadimefon: Trinity, Triton 3 L 14-28 triticonazole: monium fertilizers off leaves if applied when temperatures will Combination Products ° C) to prevent foliar burn. Maintain adequate exceed 80 ° F (27 28 Briskway 11 + 3 L azoxystrobin + difenoconazole: nitrogen. Remove affected patches and re-sod if practical. 28 azoxystrobin + propiconazole: Headway, 11 + 3 3.5 On sites with a low manganese level and a history of take-all Goliath patch, apply 2 lb soluble manganese/acre as a foliar fertilizer Honor Intrinsic 28 boscalid + pyraclostrobin: 7 + 11 L chlorothalonil + propiconazole: M5 + 3 L 1-2x @ 14 Concert, in the spring, avoiding summertime applications because of Concert II - phytotoxicity risk. (For example, apply 5.5 lb manganese sul M5 + 3 L 28 E-Scape ETQ chlorothalonil + tebuconazole: fate/acre to achieve 2 lb manganese/acre.) Rates as high as 6 lb L 11 + M5 Fame C fluoxastrobin + chlorothalonil: 28 Disarm M 11 + 3 L 28 fluoxastrobin + myclobutanil: manganese/acre may be needed on soils deficient in manganese. 11 + 3 L Fame+T 28 fluoxastrobin + tebuconazole: Applications of manganese sulfate should be applied in high b PCNB + tebuconazole: Oreon 14+3 14-28 L spray volumes sufficient to penetrate the thatch, since a low pyraclostrobin + fluxapyroxad: Lexicon 28 L 11 + 7 spray volume could cause the material to be chemically bound in pyraclostrobin + triticonazole: 11 + 3 L 28 Pillar trifloxystrobin + triadimefon: 11 + 3 L 1-2x @ 28 Armada, Tartan the foliage and removed with clippings. Some high-manganese, a NC = Not classified. greens-grade fertilizers on the market would supply as much as b Do not apply to cool-season turf at daytime temperatures of 85°F or high - 6.5 lb of manganese/acre, and they may also be useful to con - er. Combine with a pigment to mask chlorosis that may occur at high label rate. After application, immediately irrigate with 1/4 inch water. trol take-all. However, most of the specialty greens fertilizers on the market contain very low amounts of manganese, and it * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most 1 = no N = control is inconsistent between experiments but performs well in some instances; experiments; = fair to good control in most experiments; 2 = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 30

31 would take perhaps a dozen applications to supply the amount F (7-16 of 45-60 ° ° C). For conditions of severe disease pressure, of manganese necessary to reduce take-all pressure. several applications at 21- to 28-day intervals beginning in early- - Sprayed fungicides should be applied in at least 5 gal of wa April are often necessary. For sites where symptoms appear or ter/1,000 sq ft or followed immediately (before they dry) with worsen during summer, studies indicate that treatments are 0.125-0.25 inch of irrigation to wash fungicide into the root often needed in springtime; consider a fungicide application zone. Granular fungicides should be applied when the turf when springtime soil temperature at a 2-inch depth averaged is dry and then watered into the soil. Several studies suggest F (13 over five days exceeds 55 C). Curative applications of ef - ° ° that, for outbreaks that develop during springtime, the most fective fungicides in early-summer have been shown to speed important time to treat preventively with fungicide is from mid- turf recovery. See product labels for specifics on application September into early-November; target fungicide applications timing. High labeled rates have been needed for best results in when average soil temperatures at a 2-inch depth are in the range several studies. 25. Yellow Patch (Low Temperature Brown Patch) 25. Yellow Patch (Low-temperature Brown Patch) Ceratobasidium cereale (Rhizoctonia cerealis) Pathogen: a -lay ] ah ium ] [ siri- sid Pronunciation: [ sarah-towba- -liss ] [ rizoc- toe -nia ] [ siri- ah tions (x) Efficacy* FRAC Interval Code (days) or Applica- Some Trade Names Fungicide: Creeping bentgrass, Kentucky bluegrass, annual Principal hosts: 28 azoxystrobin: Heritage 11 3 bluegrass Daconil Ultrex 2.5 M5 chlorothalonil: 7-14 October-April Season: 2.5 12 1x fludioxonil: Medallion 11 L 28 Fame fluoxastrobin: Improve soil drainage and reduce excessive thatch. Autumn 7 3 21-28 flutolanil: Prostar applications of nitrogen may help the turf outgrow symptoms Tourney metconazole: 3 L 1-2x the following spring, particularly when an application is made 19 7-14 L Affirm polyoxin D: after the last mowing. For sites with a chronic, recurring 2.5 1x propiconazole: Banner Maxx, Spectator, 3 Savvi problem, a nitrogen application in November is important in 7-14 Reynoutria sachalinensis: Regalia PTO NC L preventing late-winter turf damage. Mow as needed to avoid tall, L 1-2X @ 21-28 tebuconazole: Torque, Mirage Stressgard, 3 dense growth. Of the two species, annual bluegrass is the more Sipcam Clearscape ETQ, Offset, ArmorTech TEB360 susceptible host. On creeping bentgrass, infections typically are 1 thiophanate-methyl: 14 3336 EG, Fungo, L - confined to leaf blades only; symptoms usually disappear with Systec 1998, Cavalier, T-Storm out fungicide treatment with the onset of warm weather and L Trinity, Triton 21-28 triticonazole: 3 regular mowing; treat only if the disease is a chronic, recurring Combination Products azoxystrobin + acibenzolar-S-methyl: 11 + P1 L 14-28 problem. Limited field experiences suggest that azoxystrobin Heritage Action is the preferred fungicide for curative treatments on an annual azoxystrobin + chlorothalonil: Renown L 14-28 11 + M5 bluegrass. 14-28 Briskway 11 + 3 L azoxystrobin + difenoconazole: L azoxystrobin + propiconazole: Headway, 11 + 3 28 Goliath azoxystrobin + tebuconazole: 1-2x @14-21 ArmorTech L 11 + 3 ZOXY-T, StrobeT 14-21 chlorothalonil + fludioxonil + L M5 + 12 + 3 Instrata propiconazole: fluopyram + trifloxystrobin: Exteris 7+11 L 21-28 Stressgard fluoxastrobin + chlorothalonil: Fame C 11 + M5 L 14-28 L 28 11 + 3 Disarm M fluoxastrobin +myclobutanil: fluoxastrobin + tebuconazole: 11 + 3 Fame+T L 21-28 b PCNB + tebuconazole: Oreon 21-28 14+3 L SysStar thiophanate-methyl + flutolanil: L 1 + 7 21-28 a NC = Not classified b - Do not apply to cool-season turf at daytime temperatures of 85°F or high er. Combine with a pigment to mask chlorosis that may occur at high label rate. After application, immediately irrigate with 1/4 inch water. * Rating system for fungicide efficacy: 4 = consistently good to excellent control in published experiments; 3 = good to excellent control in most 1 = no N = control is inconsistent between experiments but performs well in some instances; experiments; = fair to good control in most experiments; 2 = intermediate between two efficacy categories. efficacy; L = limited published data on effectiveness; + 31

32 26. Yellow Tuft 26. Yellow Tuft * b Pathogen: Sclerophthora macrospora a -a ] Pronunciation: spore -thora ] [ macro- off [ scler- Principal hosts: Creeping bentgrass, Kentucky bluegrass, annual FRAC Efficacy Interval Code (days) Some Trade Names Fungicide: bluegrass, perennial ryegrass L Chipco Signature, Signature Xtra fosetyl Al: 21 33 April-September Season: Stressgard mefenoxam: 7-21 4 2.5 Subdue MAXX Improve soil drainage and reduce excessive thatch. Brushing 21 phosphite (salts of phosphorous): 33 L Appear, Alude, or grooming can be used to dislodge severely infected plants. Biophos, Fiata Stressgard, Magellan, Resyst, Vital Application of nitrogen fertilizer may mask symptoms but 1 Insignia Intrinsic pyraclostrobin: 11 14-28 - doesn’t reduce infection. For curative control, two to three ap Regalia PTO L NC 7-14 Reynoutria sachalinensis: plications of a fungicide listed in the accompanying table may Combination Products 7 + 11 L 14-28 boscalid + pyraclostrobin: Honor Intrinsic be necessary. M5 + 1 L 14 chlorothalonil + thiophanate-methyl: ConSyst, Spectro, Broadcide, Peregrine, Tee-1-Up, TM/C 11 + 7 Lexicon pyraclostrobin + fluxapyroxad: 14-28 L pyraclostrobin + triticonazole: Pillar 11 + 3 L 14-28 a NC = Not classified b Efficacy ratings pertain to curative applications; efficacy of preventive ap - plications are unavailable. Useful Web Resources Web-based resources that may prove useful to readers include the following: University of Kentucky Turfgrass Science Program: http:// y www.uky.edu/Ag/ukturf/ y Rutgers Plant Diagnostic Laboratory: https://njaes.rutgers. edu/plantdiagnosticlab/ y Rutgers University Center for Turfgrass Science: http://www. turf.rutgers.edu/ y Identification of turfgrass species: http://www.agry.purdue. edu/turf/tool/index.html y Disease identification: http://turfdiseaseid.ncsu.edu/ National Turfgrass Evaluation Program: http://www.ntep.org/ y y NC State University – TurfFiles: http://www.turffiles.ncsu.edu Mention or display of a trademark, proprietary product, or firm in text or figures does not constitute an endorsement and does not imply approval to the exclusion of other suitable products or firms. Educational programs of Kentucky Cooperative Extension serve all people regardless of economic or social status and will not discriminate on the basis of race, color, ethnic origin, national origin, creed, - religion, political belief, sex, sexual orientation, gender identity, gender expression, pregnancy, marital status, genetic information, age, veteran status, or physical or mental disability. Issued in further ance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Nancy M. Cox, Director of Cooperative Extension Programs, University of Kentucky College of Agriculture, Food and Environment, Lexington, and Kentucky State University, Frankfort. Copyright © 2017 for materials developed by University of Kentucky Cooperative Extension. This publication may be reproduced in portions or its entirety for educational or nonprofit purposes only. Permitted users shall give credit to the author(s) and include this copyright notice. Publications are also available on the World Wide Web at www.ca.uky.edu. Revised 4-2017

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