Late blight thrives in cool, wet weather, and under such conditions can damage potatoes quickly. The first symptoms of the disease usually appear on lower leaves as small, light-to-dark green, circular or irregular-shaped water-soaked spots. White cottony mildew develops on and around these foliar lesions. Stems, petioles, and tubers are also susceptible to late blight. Dry weather may interrupt the disease cycle, but if damp weather returns late blight will continue to progress.

In the following Spud Doctor video, Kiran Shetty, technical product lead for Syngenta, talks late blight and how research at the Syngenta Vero Beach Research Center tests management tools in the field under real conditions. Orondis® Opti fungicide, a combination of oxathiapiprolin and chlorothalonil, is one such tool. It protects the potatoes under heavy late blight pressure to help maximize marketable yields.

Want more information about potato diseases in your area? Growers in or near ID, MI, ND, OR and WA can sign up to receive text messages when the Syngenta Late Blight Hotline is updated. The hotline features key university researchers providing timely advice from area experts on the latest weather conditions, disease-control measures and disease pressures.

Sign up for the Know More, Grow More Digest to receive twice-monthly agronomic e-mail updates pertinent to your area.

All photos are either the property of Syngenta or are used with permission.