Date of Award
5-2018
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Committee Member
Dr. Guido Schnabel, Committee Chair
Committee Member
Dr. Paula Agudelo
Committee Member
Dr. Sydney Everhart
Committee Member
Dr. Julia Kerrigan
Abstract
Gray mold is one of the most devastating diseases infecting strawberries worldwide. Though Botrytis cinerea is the most common causal agent of this disease, five other species are also currently known to cause gray mold on strawberry: Botrytis pseudocinerea, Botrytis caroliniana, Amphobotrys ricini, Botrytis mali, and Botrytis fragariae. This work focuses on the newly described species B. fragariae in the Mid-Atlantic United States: its discovery, distribution, and fungicide resistance patterns. B. fragariae was originally detected in a study of Botrytis species infecting German strawberry fields. It was later detected in the United States through research on the fungicide polyoxin D. Isolates were found with reduced sensitivity to this fungicide, though polyoxin D had not been applied in the locations where reduced sensitivity was detected. This reduced sensitivity was later found to be characteristic of many isolates of B. fragariae. Further characterization of this species revealed an apparent preference for strawberry flower over fruit tissue, and a seeming absence of B. fragariae in nurseries producing strawberry transplants. When B. fragariae and B. cinerea were compared in fungicide resistance profiles and chemical class resistance profiles, both profiles were different between species. Most importantly, B. fragariae isolates did not exhibit resistance to the Succinate Dehydrogenase Inhibitor fungicides, but exhibited higher frequencies and levels of resistance to the commonly used active ingredient fludioxonil than B. cinerea. Future work is necessary to investigate B. fragariae’s genetic differences from B. cinerea, to further understand its geographic distribution, and to show the relative importance of this species to strawberry production worldwide.
Recommended Citation
Dowling, Madeline Elizabeth, "Detection and Characterization of the Newly Described Species Botrytis fragariae Causing Gray Mold on Strawberries in the United States" (2018). All Dissertations. 2155.
https://tigerprints.clemson.edu/all_dissertations/2155