A case of late blight on tomatoes from Northern KY was confirmed yesterday by the Plant Disease Diagnostic Lab at the Univ. of KY. yesterday. Additional findings were found today.
Up until last year, late blight has not been a common disease for us in KY, and we expect to see it much later in the year. However, this now marks the second year in a row in which this disease has appeared much earlier than usual. Last year, we suffered the most severe outbreak of late blight that we’ve ever recorded.
We definitely want to play it safe with late blight. Commercial producers, both commercial and homeowners alike, need to be on a regular spray schedule of fungicides for disease control. Spraying insecticides will not prevent diseases such as this.
Chlorothalonil and mancozeb are good protectant fungicides against late blight, and copper is moderately effective. These materials are the best bets for homeowners, and coppers (i.e., fixed copper) are probably the only reliable protectant option for organic producers. Acrobat (now sold as Forum), Revus (new from Syngenta), Presidio (new from Valent), and Ridomil Gold Bravo are products that have specific activity against late blight.
Kenneth W. Seebold, Jr.
Assistant Extension Professor
Tobacco and Commercial Vegetables
University of Kentucky, Dept. of Plant Pathology
205 Plant Science Building
Lexington, KY 40546
office tel: 859.257.7445 x80721
KY Tobacco Disease Information Page: