Disease Potential for Hurricane Impacted Tobacco
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Hurricane Florence has brought damaging rains, winds, and flooding to North Carolina with, in some areas, tobacco still being on the stalk. Continuing rains from the edges of Florence are giving rise to conducive conditions in much of the state for Brown spot (Alternaria alternata), Target spot (Rhizoctonia solani), Frogeye leaf spot (Cercospora nicotianae), and bacterial blight. Brown spot and target spot still appear to be sensitive to azoxystrobin in NC. Resistance to strobilurins has been found in Frogeye leaf spot populations this year in several counties of NC. It is certainly possible that because of this, frogeye leaf spot could continue to worsen regardless of fields having been sprayed with a fungicide. Because of residue concerns, making a fungicide application before harvest is not recommended. Harvesting any remaining crop as quickly as possible after the remaining storms pass through the state appears to be the best option at this point. Destroying crop debris quickly after harvest will also benefit next year’s crop, since extensive Granville wilt and leaf diseases were observed throughout this growing season in much of the state.
Curing leaf that has extensive brown spot or excess moisture may also be problemmatic for any remaining harvestable tobacco. The conditions in the curing process are conducive for brown spot growth, and affected leaves may continue to rot if there’s enough moisture for the fungus. If leaves are going into the barn with extensive brown spot, ensuring that the leaves are completely dry before beginning the curing process will help. If leaves are damp going into the barn, it may be worth running the fans before curing, with space and time permitting, to reduce moisture on leaf surfaces.
As always, if there are questions about diseases or options for a specific problem, don’t hesitate to reach out to local N.C. Cooperative Extension or the tobacco specialist team for help.