angular leaf spot of watermelon
Angular leaf spot-Almost always observed in transplant greenhouses, this disease is seldom observed in the field. Note water-soaked lesions with irregular margins and at least some chlorosis. Disease more common in cool conditions. Not usually an important disease, however, it may be confused with bacterial fruit blotch.
Figure 1. Angular leaf spot of watermelon includes round, light brown necrotic lesion with chlorotic halo. 
Figure 2. Angular leaf spot on watermelon leaf has caused dark, necrotic lesion on cotyledon. 
Figure 3. Several watermelon transplants have lesions of angular leaf spot.