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Bacterial Spot Danger

In reviewing the weather forecasts for the next 15 days or so, I am concerned about bacterial spot development.  The current warm temperatures are certainly increasing bacterial numbers, and any temperature above 65 F is sufficient for multiplication.  Temperatures in the upper 70s or lower 80s provide perfect conditions for bacterial multiplication and disease development.  Moisture is also needed, and we have plenty of that on the way as well if the forecasts are accurate.  Petal fall and shuck split are critical time periods for infection of leaves and fruit, but the highly susceptible timeframe extends for a 2-3 week period immediately after bloom, and it tapers off gradually.  I think most producers are aware of the danger, and I likewise think that they are spraying according to the IPM guide for peaches and nectarines, but now would be a good time to panic if coppers are not applied in sufficient amounts to address the disease.  I think it will be possible that moderately resistant varieties will have issues this year as well.  Again, application of bacterial spot materials will be critical over the next few weeks, and I hope the weather will not work against us. 

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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.