Late blight and downy mildew have been confirmed in Ohio. Downy mildew was found June 23 on cucumbers in Wayne and Holmes counties in northeast Ohio, following reports of the disease in Ontario, Canada, the previous week.
Late blight was confirmed around the same time on tomatoes on an organic farm in Harrison County in east-central Ohio. This follows confirmations of late blight in tomatoes and/or potatoes in Michigan, Pennsylvania, Kentucky and New York.
“What’s different this year is that both diseases have appeared in Ohio earlier than we have seen before,” said Sally Miller, a vegetable pathologist with Ohio St. Univ. Extension and the Ohio Ag. Research and Development Center.
If left unmanaged, both downy mildew and late blight can result in complete destruction of crops. Recent storms likely created favorable conditions for the diseases to occur since the pathogens’ spores are carried by winds and they thrive in wet environments.
Pictured: Small necrotic or chlorotic flecks appear on the upper leaf surface of downy mildew-infected cucurbit leaves.
Photo courtesy of T.A. Zitter, Cornell Univ.