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Botrytis Sighting and Botrytis Sampling for Fungicide Resistance

There is a big hairy beast starting to show up out there, and unfortunately, it is not Big Foot.  We are starting to observe Botrytis in some vineyards, so it is time to scout for this pathogen.  Cain Hickey took this photo, and he states the following: “This is a reminder to pay attention to canopy management and your fungicide sprays.
The picture, below, was taken in a very-well managed Chardonnay vineyard. However, this particular panel did not have leaves removed. This is a good example of what can happen when canopies are not managed and weather patterns exacerbate fungal disease development – even in intensively-managed vineyards.”

If you are observing Botrytis at this time, this might simply be the result of heavy rains and ideal temperature for Botrytis development. However, it could be resistance.  While there is still time to act relative choosing the most effective botryticides for the remainder of the season, this would be a good time to send off Botrytis samples to Clemson University (Dr. Guido Schnabel) for resistance testing.  Instructions can be found below, but please interact with your local county agent to make this happen.  This testing will help you to understand the Botrytis resistance profile at your particular vineyard, and it will keep you from wasting time and money on spraying fungicides that are not efficacious — resulting in poor or nonexistent Botrytis management.

PS – Hope to see many of you at the vineyard meeting next week at Wolf Mountain – see Clark’s June 5th post for more information.


Botrytis bunch rot on Chardonnay

Botrytis Collection Instructions


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About Phil Brannen

Phil Brannen is a Professor in the Plant Pathology Department at the University of Georgia. He attended the University of Georgia for his undergraduate degree in Plant Protection and Pest Management, where he also received an M.S. in Plant Pathology, followed by a Ph.D. in Plant Pathology from Auburn University. He has extensive experience with disease management programs in numerous cropping systems. He serves as the extension fruit pathologist for Georgia – conducting research and technology transfer for multiple fruit commodities. His efforts are directed towards developing IPM practices to solve disease issues and technology transfer of disease-management methods to commercial fruit producers. He also teaches the graduate level Field Pathology Course, the History of Plant Diseases and their Impact on Human Societies Course, team-teaches the IPM Course, coordinates the Viticulture and Enology in the Mediterranean Region Course (Cortona, Italy), and guest lectures in numerous other courses throughout the year.