ISSN:
1573-8469
Keywords:
DMI
;
dollar spot
;
fungicide resistance
;
turfgrass
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Isolates of Sclerotinia homoeocarpa were collected from across southern Ontario from areas where demethylation inhibiting fungicides reportedly had never been used. Forty of these isolates with propiconazole EC50 values ranging from 0.003 to 0.069 µg ml-1 were inoculated onto creeping bentgrass (Agrostis palustris) in summer 1995 and summer 1996 to assess virulence. Each isolate was grown on mixed cereal grains, dried, ground up and applied separately at a rate of 10 g m-2 to 0.25 m2 plots with three replicates per isolate. For both years, no spots were visible on the plots at time of inoculation; however, by the end of each experiment, there were up to 180 spots per plot with significant differences between isolates. Growth rate in culture was not significantly related to fungicide sensitivity (log-EC50 values). Statistically significant negative relationships were found in both years between AUDPC and log-EC50 values. These significant relationships imply that in the absence of propiconazole use, isolates that are more sensitive to propiconazole may out-compete isolates that are less sensitive. However, further study is required to determine the time frame for this to occur, and whether DMI-resistance prevention strategies can feasibly be based on the existence of resistance-related fitness costs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008614832692
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