By Andi Anderson
Farmers in Ohio are closely watching their cucumber and squash fields as two major crop diseases—downy mildew and Phytophthora blight—are expected to appear soon. Though no cases have been confirmed yet in sentinel plots at Fremont, Huron, Wayne, or Piketon, rising spore activity in nearby states and suitable weather conditions make it likely that these diseases will reach Ohio fields.
Downy mildew was confirmed on cucumbers in eastern North Carolina on June 10 and in Michigan by June 26. In both cases, disease spread was helped by humid conditions, cool temperatures, and extended leaf wetness. These same weather conditions—warm nights, humid afternoons, and frequent rain—are now common in Ohio.
Phytophthora blight, which thrives in warm and saturated soils, has already been found in some Ohio cucurbit fields. Symptoms include water-soaked crowns, black slimy lesions near the soil line, and sudden wilting. Good drainage, crop rotation, and reduced overhead irrigation can help reduce its spread.
To detect both diseases early, experts recommend checking leaves weekly for signs like angular yellow spots and gray mold (downy mildew) or wilting and rot near the roots (Phytophthora). Suspect samples should be sent to the OSU Plant and Pest Diagnostic Clinic for confirmation.
For treatment, products like Orondis Opti, Ranman, and Zampro have proven effective against downy mildew. Farmers are advised to rotate fungicides to prevent resistance.
Preventing Phytophthora spread requires good field selection, raised beds, and careful water use. Sanitation practices such as cleaning tools and removing crop residues are also important.
With the right actions now, farmers can better manage these threats and protect their harvest.
Photo Credit: gettyimages-fotokostic
Categories: Ohio, Crops