downy mildew of cucumber

Downy mildew-The presence of this disease in Indiana depends on the arrival of spores of the causal fungus-like organism each year. Such spores are more likely to arrive in August or later. The chlorotic lesions of downy mildew on cucumber are angular. Multiple lesions may coalesce to encompass large areas of the leaf. Under moist conditions, the causal fungus-like organism may sporulate, becoming visible on the underside of the leaf. Stems and fruit are not directly infected.

Figure 1. Downy mildew of cucumber. Note angular chlorotic lesions. Figure 1. Downy mildew of cucumber. Note angular chlorotic lesions.
Figure 2. Downy mildew of cucumber. Note angular chlorotic lesions. Figure 2. Downy mildew of cucumber. Note angular chlorotic lesions.
Figure 3. Downy mildew of cucumber. Figure 3. Downy mildew of cucumber.
Figure 4. Downy mildew of cucumber. Note dark, sporulation visible on the underside of the leaf. Figure 4. Downy mildew of cucumber. Note dark, sporulation visible on the underside of the leaf.
Figure 5. Downy mildew of cucumber. Note chlorotic and necrotic lesions. Figure 5. Downy mildew of cucumber. Note chlorotic and necrotic lesions.