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Poster: Diseases of Plants: New & Emerging Diseases


New Botrytis species affecting strawberry on the east coast
G. SCHNABEL (1), M. Dowling (1), M. Hu (1) (1) Clemson University, U.S.A.

We detected a new species of Botrytis infecting strawberries in the United States. While monitoring fungicide resistance of 459 Botrytis isolates collected from South Carolina (211), Maryland (123), North Carolina (101), Virginia (17), and Ohio (7), we observed isolates with phenotypes different from typical Botrytis cinerea. These isolates produced fluffy, white mycelium and sporulated poorly on potato dextrose agar, minimal medium, strawberries, apples, and tomatoes. These isolates were found in 11 different locations across South Carolina (20), and North Carolina (4). The G3PDH gene was sequenced for these isolates and nucleotide BLAST search revealed that they formed a cluster separate from Botrytis species previously described. Further sequencing of RPB2, Hsp60, NEP1, and NEP2 genes for three representative isolates revealed that these isolates were identical to isolates of Botrytis fragariae, a species recently discovered infecting strawberry in Germany, but never before observed in the United States. In order to determine the distribution and prevalence of this species in the eastern United States, primers were developed that distinguish Botrytis cinerea and Botrytis fragariae. Preliminary data suggest that Botrytis fragariae isolates are more likely to have reduced sensitivity to the new fungicide polyoxin D. The discovery of a new species of Botrytis causing gray mold of strawberry may require adjustments in gray mold management strategies.