Scout Frequently for Late Blight on Tomato

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Late blight on tomato leaf

Late blight on tomato leaf. Photo by I. Meadows

Late blight, caused by the oomycete Phytophthora infestans, was reported on tomato this week from 13 counties in Arkansas. The disease was first observed as early as May and June, but was not reported to the USABlight website until earlier this week. To date, there have been no reports of tomato late blight in North Carolina.

If environmental conditions are favorable, late blight can severely defoliate tomato plants and cause significant lesions on fruit within several days. Regular and frequent scouting of tomato fields for late blight is strongly recommended; effective management relies on early detection. Consider preventive fungicide applications to protect tomato crops from late blight, particularly in some counties of western North Carolina where there has been significant rainfall and heavy dews favoring disease outbreak.

For more information about tomato late blight and management, including effective fungicides, visit the disease fact sheet on tomato late blight. Control recommendations are also available in the USAblight website. You also can register to receive text and/or email alerts when new disease outbreaks are reported.

If you think you have late blight on your tomatoes, 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 submit a report on the USAblight website to alert other growers in the area.