Early blight fungus spreads in much the same way as the late blight fungus. However, early blight is favored by warm weather, late blight by cool, wet weather. Among the compounds registered for use in Connecticut are chlorothalonil, maneb, and mancozeb. Consult the label for dosage rates and safety precautions. This wilt, which has become general in Connecticut fields, is most evident in late August and September.
Lower leaves become yellow and die, and the denuded stem holds up a flag of wilted upper leaves.
The inside of the stem is discolored. The vascular ring may be discolored at the stem-end of the tuber. Verticillium is carried in seed and soil and infects the plant beneath the ground. Seed from severely infected fields increases infection. This fungus attacks the plant beneath the ground and in severe infections kills sprout before they reach the surface.