scholarly journals Dollar Spot and Brown Patch Incidence in Creeping Bentgrass as Affected by Acibenzolar-S-Methyl and Biostimulants

HortScience ◽  
2003 ◽  
Vol 38 (6) ◽  
pp. 1223-1226 ◽  
Author(s):  
Joon Lee ◽  
Jack Fry ◽  
Ned Tisserat
Keyword(s):  
Experimental Design ◽  
Plant Defense ◽  
Cultural Practices ◽  
Creeping Bentgrass ◽  
Sclerotinia Homoeocarpa ◽  
Agrostis Palustris ◽  
Dollar Spot ◽  
Putting Greens ◽  
Brown Patch ◽  
Turf Quality

There is interest in identifying cultural practices that may reduce fungicide requirements of creeping bentgrass (Agrostis palustris Huds.) putting greens. Our objective was to evaluate the plant defense activator ASM in combination with 12 biostimulants for the potential to reduce dollar spot (Sclerotinia homoeocarpa F.T. Bennett) and brown patch (Rhizoctonia solani Kuhn) in a blend of `Cato: `Crenshaw creeping bentgrass during 2000 and 2001. The experimental design was a split-plot with ASM as the whole plot, and biostimulants as the subplots. ASM was applied biweekly as a.i. at 35 g·ha-1 and biostimulants were applied according to manufacturers recommendations. Sclerotinia homoeocarpa infection centers were reduced by 38% with ASM, but levels were >1500/m2 in Aug. 2000, and turf quality was unacceptable through most of the study period. No suppression of brown patch occurred with ASM. None of the biostimulants reduced dollar spot or brown patch in creeping bentgrass when compared to biweekly applications of soluble N at 4.9 kg·ha-1. Dollar spot suppression achieved with ASM warrants additional studies to determine how it might be used to reduce fungicide inputs on creeping bentgrass putting greens. Chemical name used: acibenzolar-S-methyl (ASM).

Dollar Spot in Four Bentgrass Cultivars as Affected by Acibenzolar-S-Methyl and Organic Fertilizers

2003 ◽  
Vol 4 (1) ◽  
pp. 5 ◽  
Author(s):  
Joon Lee ◽  
Jack Fry ◽  
Ned Tisserat
Keyword(s):  
Organic Fertilizer ◽  
Creeping Bentgrass ◽  
Organic Fertilizers ◽  
Sclerotinia Homoeocarpa ◽  
Agrostis Palustris ◽  
Dollar Spot ◽  
Putting Greens ◽  
Brown Patch ◽  
Growing Seasons ◽  
Progress Curve

Golf course superintendents are interested in identifying ways to reduce fungicide inputs on creeping bentgrass (Agrostis palustris Huds.) putting greens. Our objectives were to evaluate the influence of the plant defense activator acibenzolar-S-methyl (ASM, Actigard, Syngenta Corp., Basel, Switzerland) and organic fertilizers on dollar spot (Sclerotinia homoeocarpa F.T. Bennett) and brown patch (Rhizoctonia solani Kuhn) in four bentgrass cultivars. Crenshaw had over 10 times the area under the disease progress curve (AUDPC) value for dollar spot compared to the cultivar L-93 in 2000. Acibenzolar-S-methyl applied at 35 g a.i. per ha every 14 days between mid-May and mid-September for two consecutive growing seasons reduced the number of S. homoeocarpa infection centers by 15% in Crenshaw, 24% in Penncross, and 29% in Providence, but had no effect on the number of infection centers in L-93. Only Sustane (Crenshaw in 2000) and Milorganite (Crenshaw and Providence in 2001) suppressed dollar spot compared to urea. The following fertilizers resulted in an increase in S. homoeocarpa infection centers: Nature Safe 8-1.3-4.2 in Crenshaw in both years, and in Providence in 2000; Nature Safe 10-0.9-6.6 in Crenshaw in both years; and Sustane with Iron in Crenshaw in 2001. All other organic fertilizer × cultivar combinations resulted in dollar spot levels equivalent to those observed in ureatreated turf. Brown patch levels were not affected by cultivar, ASM, or organic fertilizers. The defense activator ASM deserves further evaluation as a tool to reduce dollar spot-targeted fungicide inputs in creeping bentgrass. Accepted for publication 5 June 2003. Published 26 June 2003.

RELATIONSHIP BETWEEN WEATHER FACTORS AND DOLLAR SPOT OF CREEPING BENTGRASS

1984 ◽  
Vol 64 (1) ◽  
pp. 167-174 ◽  
Author(s):  
ROBERT HALL
Keyword(s):  
Disease Control ◽  
Creeping Bentgrass ◽  
Weather Conditions ◽  
Acceptable Level ◽  
Sclerotinia Homoeocarpa ◽  
Agrostis Palustris ◽  
Dollar Spot ◽  
Weather Factors ◽  
Average Temperature

In 1981 and 1982 epidemics of dollar spot of creeping bentgrass, caused by Sclerotinia homoeocarpa, proceeded in a series of steps. Each step began at a point where a decline in the epidemic rate was followed by an increase in the epidemic rate and continued until a new step began. A step in the epidemic occurred after two consecutive wet days if the average temperature for the period was at or above 22 °C or after three or more consecutive wet days if the average temperature for the period was 15 °C or greater. These weather conditions were referred to as "infection periods." In 1982, an application of Tersan 1991 (benomyl) 1 and 2 days after two infection periods provided an acceptable level of disease control as effective as that obtained from a regular preventive schedule of seven sprays.Key words: Agrostis palustris, disease control, Sclerotinia homoeocarpa, weather-timed spray

scholarly journals Brachypodium: A Potential Model Host for Fungal Pathogens of Turfgrasses

2017 ◽  
Vol 107 (6) ◽  
pp. 749-757 ◽  
Author(s):  
Renee A. Rioux ◽  
Benjamin J. Van Ryzin ◽  
James P. Kerns
Keyword(s):  
Fungal Pathogens ◽  
Molecular Mechanisms ◽  
Brachypodium Distachyon ◽  
Creeping Bentgrass ◽  
Sclerotinia Homoeocarpa ◽  
Dollar Spot ◽  
Cool Season ◽  
Host System ◽  
Brown Patch ◽  
Compatible Interactions

Brachypodium distachyon is a C3 grass that is an attractive model host system for studying pathogenicity of major turfgrass pathogens due to its genetic similarity to many cool-season turfgrasses. Infection assays with two or more isolates of the casual agents of dollar spot, brown patch, and Microdochium patch resulted in compatible interactions with B. distachyon inbred line Bd21-3. The symptoms produced by these pathogens on Bd21-3 closely resembled those observed on the natural turfgrass host (creeping bentgrass), demonstrating that B. distachyon is susceptible to the fungal pathogens that cause dollar spot, brown patch, and Microdochium patch on turfgrasses. The interaction between Sclerotinia homoeocarpa isolates and Brachypodium ecotypes was also investigated. Interestingly, differential responses of these ecotypes to S. homoeocarpa isolates was found, particularly when comparing B. distachyon to B. hybridum ecotypes. Taken together, these findings demonstrate that B. distachyon can be used as a model host system for these turfgrass diseases and leveraged for studies of molecular mechanisms contributing to host resistance.

Use of TEM in Plant Disease Diagnosis: A Xylem-Limited Bacterium Associated with Diseased ‘Toronto’ Creeping Bentgrass

1981 ◽  
Vol 39 ◽  
pp. 414-415
Author(s):  
Karen K. Baker ◽  
David L. Roberts
Keyword(s):  
Osmium Tetroxide ◽  
Plant Disease ◽  
Leaf Tissue ◽  
Infectious Agent ◽  
Creeping Bentgrass ◽  
Disease Diagnosis ◽  
Unknown Etiology ◽  
Agrostis Palustris ◽  
Putting Greens ◽  
Plant Disease Diagnosis

Plant disease diagnosis is most often accomplished by examination of symptoms and observation or isolation of causal organisms. Occasionally, diseases of unknown etiology occur and are difficult or impossible to accurately diagnose by the usual means. In 1980, such a disease was observed on Agrostis palustris Huds. c.v. Toronto (creeping bentgrass) putting greens at the Butler National Golf Course in Oak Brook, IL.The wilting symptoms of the disease and the irregular nature of its spread through affected areas suggested that an infectious agent was involved. However, normal isolation procedures did not yield any organism known to infect turf grass. TEM was employed in order to aid in the possible diagnosis of the disease.Crown, root and leaf tissue of both infected and symptomless plants were fixed in cold 5% glutaraldehyde in 0.1 M phosphate buffer, post-fixed in buffered 1% osmium tetroxide, dehydrated in ethanol and embedded in a 1:1 mixture of Spurrs and epon-araldite epoxy resins.

Control of Silvery-Thread Moss (Bryum argenteum Hedw.) in Creeping Bentgrass (Agrostis palustris Huds.) Putting Greens

2004 ◽  
Vol 18 (3) ◽  
pp. 560-565 ◽  
Author(s):  
Keith D. Burnell ◽  
Fred H. Yelverton ◽  
Joseph C. Neal ◽  
Travis W. Gannon ◽  
J. Scott McElroy
Keyword(s):  
Ferrous Sulfate ◽  
Field Experiments ◽  
Creeping Bentgrass ◽  
Nitrogen Fertilizers ◽  
Agrostis Palustris ◽  
Putting Greens ◽  
Rainfall Events ◽  
Population Reduction ◽  
Elk River ◽  
Turfgrass Quality

Field experiments were conducted to evaluate chemicals for silvery-thread moss control and bentgrass turfgrass quality. Treatments included iron (Fe)-containing products, nitrogen fertilizers, Ultra Dawn dishwashing detergent (UD) at 3% (v/v), and oxadiazon. In general, greater silvery-thread moss control was achieved with Fe-containing products. Ferrous sulfate at 40 kg Fe/ha plus ammonium sulfate at 30 kg N/ha, a combined product of ferrous oxide, ferrous sulfate, and iron humates (FEOSH) at 125 kg Fe/ha, and a combined product of iron disulfide and ferrous sulfate (FEDS) at 112 kg Fe/ha reduced silvery-thread moss populations 87, 81, and 69%, respectively, 6 wk after initial treatment (WAIT). UD reduced silvery-thread moss populations 57% 6 WAIT. The addition of oxadiazon to Fe-containing treatments did not improve silvery-thread moss population reduction. Other experiments evaluated two formulations of chlorothalonil, each applied at two rates, chlorothalonil with zinc at 9.5 and 17.4 kg ai/ha and chlorothalonil without zinc at 9.1 and 18.2 kg/ ha, and two spray volumes (2,038 and 4,076 L/ha). Greater silvery-thread moss population reduction was observed at Jefferson Landing in 1999 compared with Elk River in 1999 and 2000. Rainfall events at Elk River in 1999 and 2000 within 24 h after application and no rain at Jefferson Landing may account for variation in performance of products between sites. However, no difference in chlorothalonil formulation, rate, or spray volume was observed in any location or year. These data indicate that Fe-containing fertilizers or chlorothalonil can be used to reduce silvery-thread moss populations in creeping bentgrass putting greens.

scholarly journals Residual Efficacy of Fungicides for Control of Dollar Spot on Creeping Bentgrass

Plant Disease ◽  
2006 ◽  
Vol 90 (5) ◽  
pp. 571-575 ◽  
Author(s):  
Richard Latin
Keyword(s):  
Creeping Bentgrass ◽  
Effective Concentration ◽  
Disease Suppression ◽  
Golf Course ◽  
Sclerotinia Homoeocarpa ◽  
Dollar Spot ◽  
Residual Efficacy ◽  
Bioassay Technique ◽  
Precipitous Decline ◽  
Field Plots

The duration of effective concentrations of fungicides for control of dollar spot on creeping bentgrass fairways was investigated using a bioassay technique. In each of three runs of the experiment, fungicide treatments were applied once to turf in replicated field plots; then, the plots were sampled periodically over 3 weeks by removing turf plugs from the field. The sampled plugs were placed in incubation containers and inoculated with sections from a 4-day-old colony of Sclerotinia homoeocarpa growing on potato dextrose agar. After a 96-h incubation period, the extent of pathogen growth on the turf plugs was measured. Results described a precipitous decline in effective concentration for all fungicide treatments beginning 7 to 10 days after application. The fungicides were only marginally effective at 14 days after application, and none provided any disease suppression at 21 days after application. The efficacy half-life (EHL) associated with four of the fungicides (chlorothalonil, iprodione, propiconazole, and thiophanate methyl) was estimated with two models. EHL estimates ranged from 6.1 to 15.2 days depending on the fungicide and the model. This research contributes to our knowledge of the duration of effective fungicide concentrations on creeping bentgrass and can provide insight for scheduling fungicide sprays for golf course fairways.

scholarly journals Genetic Diversity of Sclerotinia homoeocarpa Isolates from Turfgrasses from Various Regions in North America

Plant Disease ◽  
2004 ◽  
Vol 88 (11) ◽  
pp. 1269-1276 ◽  
Author(s):  
G. Viji ◽  
W. Uddin ◽  
N. R. O'Neill ◽  
S. Mischke ◽  
J. A. Saunders
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Creeping Bentgrass ◽  
The United States ◽  
Vegetative Compatibility ◽  
Major Group ◽  
Golf Courses ◽  
Sclerotinia Homoeocarpa ◽  
Dollar Spot ◽  
Geographical Regions

Sixty-seven isolates of Sclerotinia homoeocarpa, causing dollar spot disease in creeping bentgrass, annual bluegrass, Bermudagrass, and perennial ryegrass turf, collected from 23 golf courses in various geographical regions of the United States and Canada between 1972 and 2001, were characterized by vegetative compatibility, genetic diversity, and pathogenicity. Eleven vegetative compatibility groups (VCGs A to K) were identified among the isolates tested in this study, and five of them (VCGs G to K) were new. VCG B was the most predominant group, typifying 33 isolates (51%) tested. S. homoeocarpa isolates collected from golf courses in Pennsylvania belonged to seven VCGs (A, B, E, F, G, I, and K), whereas three groups were observed in those collected from New York (B, E, and G) and New Jersey (E, H, and I). Two isolates, one each from Pennsylvania and Canada, were incompatible when paired with the tester isolates in all possible combinations, and did not fall into any known VCG. An isolate collected from Canada was compatible with tester isolates from two VCGs (C and D). Genetic analyses using amplified fragment length polymorphism (AFLP) showed the presence of two genetically distinct groups, designated as major group and the minor group. The major group included 36 isolates collected from various golf courses in the United States and Canada. Two isolates collected from bermudagrass in Florida formed a separate cluster, the minor group. Isolates that belonged to the major group were further divided into two subgroups (1 and 2). Subgroup 1 consisted of all the isolates that belonged to VCGs A, E, G, H, and I. Three of the four isolates that belonged to VCG K also were clustered with isolates of subgroup 1. Subgroup 2 consisted of all the isolates from VCG B, and one each from VCGs F and K. Pathogenicity assays on Penncross creeping bentgrass showed significant differences (P = 0.05) in virulence among the isolates. Overall, a relationship between virulence and VCGs was observed, in which certain virulence groups corresponded to specific VCGs; however, such a relationship was not observed between virulence and AFLPs. Close similarity among isolates of S. homoeocarpa collected from different locations in the United States and Canada suggests that isolates of the same genotype could be involved in outbreaks of dollar spot epidemics at multiple locations.

scholarly journals Mowing Frequency and Plant Growth Regulator Effects on Dollar Spot Severity and on Duration of Dollar Spot Control by Fungicides

Plant Disease ◽  
2011 ◽  
Vol 95 (11) ◽  
pp. 1433-1442 ◽  
Author(s):  
Alexander I. Putman ◽  
John E. Kaminski
Keyword(s):  
Plant Growth ◽  
Creeping Bentgrass ◽  
Agrostis Stolonifera ◽  
Golf Course ◽  
Sclerotinia Homoeocarpa ◽  
Dollar Spot ◽  
Confounding Effect ◽  
Residual Efficacy ◽  
The University ◽  
University Of Connecticut

Management of dollar spot (incited by Sclerotinia homoeocarpa) on golf course fairways is increasingly challenging. The objectives of this study were to determine the influence of mowing frequency and plant growth regulators (PGRs) on dollar spot severity and on the residual efficacy of fungicides for control of dollar spot. Two 4-month-long studies were conducted on ‘Putter’ creeping bentgrass (Agrostis stolonifera) maintained as a fairway at the University of Connecticut. Treatments were arranged in a three-by-three-by-five factorial that assessed the influence of mowing frequency (2, 4, or 6 days week–1) and PGRs (paclobutrazol, trinexapac-ethyl, or none) on dollar spot control by five fungicide treatments (boscalid, chlorothalonil, iprodione, propiconazole, or none). Turf was mowed in the afternoon hours to minimize the confounding effect of mowing frequency on leaf wetness duration. Treatments were initiated in the late spring of 2007 and 2008, and each fungicide treatment was reapplied only when dollar spot exceeded a threshold of five infection centers plot–1. In the absence of fungicides, dollar spot severity was reduced by 63 to 90% in plots treated with paclobutrazol and by 13 to 55% in plots treated with trinexapac-ethyl. Dollar spot severity was 23 to 50% lower in plots mown 2 days week–1 compared with those mown 6 days week–1. In cases where a significant interaction was observed between mowing frequency and PGRs, dollar spot was reduced on most rating dates in plots treated with trinexapacethyl that were mown 2 days week–1 compared with those mown 6 days week–1. Survival analysis of days until threshold was met revealed that duration of control of fungicides in plots receiving paclobutrazol were 28 to 84% longer compared with plots not receiving PGR. Duration of control by fungicides was generally similar between plots treated with trinexapac-ethyl and no PGR. In general, mowing frequency did not influence duration of control. Results from this study indicate that paclobutrazol could be used to increase the treatment interval of fungicides and that mowing frequency in the absence of dew is likely to have little influence on fungicide residual efficacy. When used without fungicides, PGRs and less frequent mowing may reduce dollar spot in situations where fungicide use is limited.

scholarly journals Variation Among Creeping Bentgrass Cultivars in Recovery from Epidemics of Dollar Spot

Plant Disease ◽  
1997 ◽  
Vol 81 (1) ◽  
pp. 99-102 ◽  
Author(s):  
P. Vincelli ◽  
J. C. Doney ◽  
A. J. Powell
Keyword(s):  
Partial Resistance ◽  
Creeping Bentgrass ◽  
Weather Conditions ◽  
Disease Outbreak ◽  
The Other ◽  
Agrostis Palustris ◽  
Dollar Spot ◽  
Fungicide Treatment ◽  
Recovery Pattern ◽  
Host Growth

Dollar spot was allowed to develop from natural inoculum in 15 cultivars of creeping bentgrass (Agrostis palustris) until epidemics were well established. At that time, initial disease intensities were assessed, and one-half of each plot was treated with cyproconazole at 0.3 kg a.i./ha. For each cultivar, disease intensities were assessed 6 to 14 days after treatment in both treated and untreated subplots. Three general patterns of recovery were observed: (i) significant recovery only with fungicide treatment; (ii) some recovery without treatment but greater recovery with treatment; and (iii) equal recovery with or without treatment. Only one cultivar exhibited the same recovery pattern in all 3 years; 10 of 15 cultivars exhibited the same pattern in 2 years of testing. In 1991 and 1993, nearly all cultivars tested recovered more quickly when treated with cyproconazole than when left untreated. In contrast, nearly half of the cultivars in 1992 exhibited the same level of recovery in both treated and untreated subplots. Weather conditions during the 1992 test period were cooler and wetter than during the other years of the study, which probably favored host growth and turfgrass recovery. While some cultivars exhibited partial resistance to dollar spot, no consistent association was found among creeping bentgrass cultivars between the level of partial resistance to, and recuperative ability from, dollar spot. Although the recuperative potential of cultivars varies in different environments, the ability to recover quickly from a disease outbreak could be a valuable cultivar attribute, particularly if it can sometimes occur without a curative fungicide application.

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