Tomato Late Blight Detected in Western North Carolina

— Written By
Late blight lesions on tomato leaf. Photo by Debbie Roos.

Late blight lesions on tomato leaf. Photo by Debbie Roos.

The following Disease Alert was written by Dr. Frank Louws, NCSU Plant Pathologist

Late blight was detected in Buncombe County, NC in the afternoon of July 10, 2015. This is the first report of late blight on tomato in North Carolina and in the southern region since January. The samples have not been confirmed by the clinic nor registered with the program yet; this will be done first thing next week. However, there is no doubt that it is late blight. The late blight pathogen can travel long distances from one county to another and from one state to another. Therefore, it is critical that growers and industry personnel actively scout their fields. If suspect samples are found they should be sent to the local extension office or contact your local cooperative extension agent for diagnosis through the Plant Disease and Insect Clinic. We will also forward samples to Cornell for typing the genotype. Growers should be prepared to switch fungicide programs to include products such as chlorothalonil in rotation with Revus Top, Presidio or Ranman and according to published recommendations in the North Carolina Agricultural Chemicals Manual page 532 or the 2015 Southeastern U.S. Vegetable Crop Handbook page 228. Organic recommendations are also available. Additional information on identification, management, including organic management, and occurrence of the disease can be found at the USAblight website. For more information about tomato late blight and how to control it see the plant pathology tomato and potato late blight fact sheets. The weather forecast the next few days in western NC is not highly conducive to late blight but the pathogen can build up rapidly under wet and cooler conditions.

For more photos, visit the Growing Small Farms website.