Fungicide Resistance Profiles for 13 Botrytis cinerea Isolates from Strawberry in Southeastern Louisiana

Fungicidal sprays are widely used for control of Botrytis fruit rot; however, the pathogen often develops resistance to frequently used fungicides. A 96-well plate micro-dilution broth bioassay developed for fungicide discovery was used to provide strawberry growers with a rapid assessment of the fungicide sensitivity of Botrytis isolates against 16 fungicides. Three sensitivity phenotypes were identified: benzimidazole and dicarboximide resistant, benzimidazole resistant and dicarboximide sensitive, and an intermediate response to both fungicides. Codon at position 198 in the beta-tubulin gene confirmed benomyl resistance. This bioassay rapidly identifies fungicide resistance and allows growers to quickly adjust their disease management strategy.