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Late Blight Confirmed on Potato in Central New Jersey

Posted: May 23, 2012

This is the first confirmed report of late blight in the region this season.
Symptoms of late blight on potato include greasy gray-brown lesions on the upper leaf surface that develop whitish-gray sporulation on the underside of the leaf surface. (Photo: Beth K. Gugino)

Symptoms of late blight on potato include greasy gray-brown lesions on the upper leaf surface that develop whitish-gray sporulation on the underside of the leaf surface. (Photo: Beth K. Gugino)

According to Andy Wyenandt, Rutgers Vegetable Pathologist, actively sporulating late blight lesions were confirmed in an 8 acre potato field in Cookstown, NJ (Burlington County). The few infected plants were found at the end of a row where the boom sprayer missed. The grower had applied preventative applications of manzate followed by chlorothalonil prior. Seed pieces were sourced from Maine. This is the first report of late blight on tomato and potato in the region this year.

Late blight can infect tomato and potato plants at any growth stage. It is important to scout regularly, recognize the symptoms and apply fungicides preventatively when conditions are favorable. Commercial fungicide recommendations for managing late blight can be found in the 2012 Commercial Vegetable Production Recommendations Guide. Organic growers should consider applying a copper-based fungicide. If you suspect late blight on your farm, please let me know via email at bkgugino@psu.edu or by phone at 814-865-7328.