Sclerotinia homoeocarpa Tolerance to Benzimidazole Configuration Fungicides

Warren, C. G.

doi:10.1094/phyto-64-1139

Cited by 43 publications

(25 citation statements)

References 4 publications

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“…The six isolates that were resistant to thiophanate-methyl in the in vitro assays caused disease severity in the thiophanate-methyl-treated plants not significantly different (P > 0.05) from non-treated controls, with relative severity always >78%. The in vitro thiophanate-methyl assay using one discriminatory concentration of 10 μg/ml corresponded to the in planta assays, consistent with prior greenhouse and field studies and the known bimodal resistance to MBC fungicides (10,30).…”

Section: In Planta Assayssupporting

confidence: 78%

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Resistance of Kansas Sclerotinia homoeocarpa Isolates to Thiophanate-Methyl and Determination of Associated β-Tubulin Mutation

Ostrander

Todd

Kennelly

2014

Plant Health Progress

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Ostrander, J. C., Todd, R. B., and Kennelly, M. M. 2014. Resistance of Kansas Sclerotinia homoeocarpa isolates to thiophanate-methyl and determination of associated β-tubulin mutation. Plant Health Progress doi:10.1094/PHP-RS-13-0120.Eighty-two isolates of Sclerotinia homoeocarpa from 12 sites in Kansas were evaluated for in vitro sensitivity to the methyl benzimidazole carbamate (MBC) fungicide thiophanate-methyl at the discriminatory dose of 10 µg/ml. Seventeen isolates were sensitive to thiophanate-methyl and the remaining isolates were resistant. Of the 65 isolates from golf course putting greens, two isolates were sensitive and the remaining 63 isolates were resistant. Six resistant and five sensitive isolates were also evaluated in greenhouse assays on fungicide-treated plants. The isolates that were sensitive to thiophanate-methyl in vitro did not cause any disease on thiophanate-methyl-treated plants, and those that were resistant in vitro caused blighting on treated plants equivalent to the nontreated controls. The entire β-tubulin gene was sequenced for four resistant and four sensitive isolates. The resistant isolates all harbored a substitution of alanine for glutamic acid at codon 198 (E198A). These results provide a starting point for further surveys and monitoring of fungicide sensitivity.

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Section: In Planta Assayssupporting

confidence: 78%

“…Specifically, resistance to MBC fungicides was first reported in the 1970s in isolates from several areas in the eastern and midwestern United States (30) and since then has been documented in numerous other locations (1,2,5,10,25). Sensitivity of S. homoeocarpa isolates to MBC fungicides has not been examined in Kansas.…”

Section: Introductionmentioning

confidence: 99%

Resistance of Kansas Sclerotinia homoeocarpa Isolates to Thiophanate-Methyl and Determination of Associated β-Tubulin Mutation

Ostrander

Todd

Kennelly

2014

Plant Health Progress

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“…Many of these fungicides, particularly systemic fungicides, successfully controlled dollar spot when they were first released, but S. homoeocarpa has developed resistance to several classes of fungicides used for dollar spot control in the United States, including earlier heavy metal-based compounds (2,18), traditional contact fungicides (21), and local or acropetal systemic fungicides such as dicarboximides (6), benzimidazoles (6,24,25), and demethylation inhibitors (DMIs) (8,11). More often than not, S. homoeocarpa exhibits crossresistance (i.e., resistance to more than one fungicide within the same chemical group) or multiple resistance (i.e., resistance to different fungicide classes) (23).…”

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confidence: 99%

Rapid Development of Fungicide Resistance by Sclerotinia homoeocarpa on Turfgrass

Jo¹,

Chang²,

Boehm³

et al. 2008

Phytopathology®

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Dollar spot, caused by Sclerotinia homoeocarpa, is the most prevalent and economically important turfgrass disease in North America. Increasing levels of fungicide resistance, coupled with tightening environmental scrutiny of existing fungicides, has left fewer options for managing dollar spot. More knowledge about S. homoeocarpa populations is needed to improve dollar spot management strategies, especially with respect to minimizing the development of fungicide resistance. Population diversity of S. homoeocarpa was examined using inter-simple sequence repeat markers and vegetative compatibility assays. Two subgroups were found in S. homoeocarpa field populations on both fairway and putting green turfgrass at a research field in Wisconsin. These subgroups were genetically different, vegetatively incompatible, and had different fungicide sensitivities. The frequency of the two genetic subgroups differed significantly between the fairway and putting green, but was uniform within the fairway or within the green. Population dynamics of S. homoeocarpa in response to two systemic fungicides (thiophanate-methyl and propiconazole) were assessed based on in vitro fungicide sensitivity. Dynamics of S. homoeocarpa populations depended on the presence of fungicide-resistant isolates in the initial populations before fungicide applications and changed rapidly after fungicide applications. Shifting of the population toward propiconazole resistance was gradual, whereas thiophanate-methyl resistance developed rapidly in the population. In conclusion, field populations of S. homoeocarpa containing genetically distinct, vegetatively incompatible groups were different on turfgrass that was managed differently, and they were changed rapidly after exposure to fungicides.

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“…This disease is the most prevalent and economically important turf disease in North America, particularly on intensively managed golf course putting greens and closely mown fairways (Couch, 1995;Vargas, 1994). However, isolates of S. homoeocarpa have developed resistance to benzimidazole, dicarboximide, and demethylation inhibitor fungicides (Cole et al, 1968;Warren et al, 1974;Detweiler et al, 1983;Golembiewski et al, 1995). The optimum temperature for disease development is 21 to 278C, though the fungus will grow over a wider range of temperature, 21 to 328C.…”

mentioning

confidence: 99%

Response of Bentgrass Cultivars to Sclerotinia homoeocarpa Isolates Representing 10 Vegetative Compatibility Groups

et al. 2006

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Dollar spot caused by Sclerotinia homoeocarpa F.T. Bennett is a major disease of turfgrass throughout the world. Current control strategies depend heavily on fungicide application. Host resistance is an alternate management strategy, but a thorough understanding of the pathogen and host interaction is required to utilize it successfully. Seventy-nine clones of 10 cultivars of creeping (A. stolonifera L.), colonial (A. capillaris L.), dryland (A. castellana Boiss. & Reut.), and velvet (A. canina L.) bentgrass species were inoculated with an isolate of S. homoeocarpa in the greenhouse. A large degree of genetic variation in response to S. homoeocarpa at the species, cultivar, and clone levels was detected. In addition, 18 isolates of S. homoeocarpa representing 10 vegetative compatibility groups (VCGs) were used to inoculate 12 bentgrass cultivars. Disease severity evaluations showed significant difference among bentgrass cultivars and species in their response to dollar spot. The colonial and velvet bentgrass cultivars were significantly less susceptible to all the isolates of S. homoeocarpa compared to the creeping bentgrass cultivars. The isolates of S. homoeocarpa showed significant differences in levels of aggressiveness. However, data from pathogenicity tests indicated a lack of racespecific interactions. Therefore, turfgrass breeders should be able to select for resistance to one or a few highly virulent isolates of the pathogen, and obtain resistance to a wide array of isolates.

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Sclerotinia homoeocarpa Tolerance to Benzimidazole Configuration Fungicides

Cited by 43 publications

References 4 publications

Resistance of Kansas Sclerotinia homoeocarpa Isolates to Thiophanate-Methyl and Determination of Associated β-Tubulin Mutation

Resistance of Kansas Sclerotinia homoeocarpa Isolates to Thiophanate-Methyl and Determination of Associated β-Tubulin Mutation

Rapid Development of Fungicide Resistance by Sclerotinia homoeocarpa on Turfgrass

Response of Bentgrass Cultivars to Sclerotinia homoeocarpa Isolates Representing 10 Vegetative Compatibility Groups

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