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Poster: Biology & Disease Mgmt: Cultural Control


Potential of heat treatment for management of Botrytis cinerea resistance on strawberry
A. ZUNIGA (1), N. Peres (1) (1) University of Florida, U.S.A.

Botrytis cinerea is the causal agent of gray mold, an important disease of strawberry in Florida. The use of fungicides to control gray mold has been exploited over the past years and as a result, resistance to many fungicide groups has been reported. In this study, we are aiming to determine the effect of a heat treatment that has proven to reduce systemic infection with Xanthomonas fragarie in strawberry propagating material on the survival of fungicide-resistant B. cinerea isolates. For this, four different B. cinerea isolates were used to evaluate survival at four temperatures (44, 48, 52 and 56oC) and seven different duration times (1, 5, 10, 30, 60, 120 and 240 min). After treatment, the spores were transferred to a growth medium to determine the percentage of spore survival. Although, B. cinerea spores survived for 1 min for all temperatures, germination was reduced by 28 to 50% at the highest temperature. Spores of all isolates exposed to 44oC for 30 min did not survive and spore germination was reduced by 7 to 16% between 48 and 52 oC for 1 min, with no spores survived for all other duration times. Previous experiments have determined that most strawberry cultivars can tolerate 44oC for up to 4 h. Thus, heat treatment of strawberry plants is a feasible strategy to produce disease-free strawberry plants and to reduce fungicide-resistant inoculum.