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Hurricanes and Phytophthora Damage

Unfortunately, it does look like Georgia will experience pretty high winds from hurricane Irma as it passes north. In addition to the direct damage to trees, tree decline and death over time can be a direct result of hurricanes and tropical storms. High winds whip young trees from side-to-side like large pom-poms, since leaves are still present, and trunks/root systems are relatively weak by comparison to larger, established trees. Trees are often laid on their sides, but even erect trees will not escape physical root and crown damage. When one adds the impact of rain-saturated soils, generally ideal for Phytophthora infection, one can see why damaged roots and wet soil will provide a “perfect storm” for root rot. Bottom line, in the following months, roots and trunks may show symptoms of Phytophthora root rot.

There is little that one can do for this type of disease once symptoms are observed. Ridomil Gold, Aliette (non-bearing trees) and Prophyt (possibly other similar products) are registered for control of these pathogens. If one incurs hurricane damage, then the time to treat would be immediately after it occurs, not when symptoms are observed. However, the chances of success under these conditions are not generally considered good. Multiple repeat treatments would also be required, so treatment would be relatively expensive as well. With this said, you need to decide now whether you want to apply fungicides immediately after the hurricane passes over.  Unfortunately, high winds in young orchards will likely result in dead and dying trees in 2018. Consider that this might be possible, and though I don’t know exactly how the various crop insurance and disaster programs work, delayed death should be part of the equation when it comes to hurricanes.

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About pbrannen

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.