Pest News: Potato Late Blight Alert

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Late blight was found on tomatoes on the Eastern shore of Virginia yesterday (June 20, 2013). Yesterday, the Plant Disease and Insect Clinic at NCSU also received pictures of a potato sample from Watauga County, NC that appears to be infected with late blight. However, this is an unconfirmed report and we are waiting for a physical sample to verify. Potato and tomato are susceptible to this disease, and can be significantly defoliated within days if environmental conditions favor the pathogen.

Active scouting and immediate action to protect potato crops in NC from late blight is recommended, since we have been experiencing wet and cool weather that is conducive to disease. For more information about potato late blight and how to control it see factsheets in english and spanish produced by Dr. Lina Quesada-Ocampo at the Department of Plant Pathology. Control recommendations are also available in the  USAblight website, where you can also register to receive text and/or email alerts when new disease outbreaks are reported.

For tomato late blight information and control recomendations please refer to the alert released by Dr. Kelly Ivors and the related factsheet for tomato late blight.

If you think you have late blight in your potatoes please contact your local Extension Agent and send photos and/or physical samples to the Plant Disease and Insect Clinic. If late blight is confirmed in your samples by an expert, please send a report at the USAblight website to alert other growers.

Control strategies are provided in the factsheets for commercial growers. Homeowners can use gardening fungicides that contain chlorothalonil as an active ingredient. Organic growers can use copper-based products to slow down disease progression.

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Late blight symptoms on potato leaf (Photo, North Carolina Plant Disease and Insect Clinic)

Late blight symptoms on potato leaf (Photo, North Carolina Plant Disease and Insect Clinic)