Edward J. Sikora, Extension Plant Pathologist, Assistant Professor, Plant Pathology Plant Disease Notes Anthracnose of Cucurbits Anthracnose, caused by the fungus Colletotrichum lagenarium, can be a destructive disease of cucurbits during warm, wet growing seasons. At least three races of Colletotrichum have been reported. The disease attacks watermelon, cantaloupe, cucumber, and gourds. Squash and pumpkin are almost immune. All aboveground plant parts are susceptible to infection, and plants can become infected at any stage in their development.
Spots are often circular to angular.
Later, spots may merge, blighting large sections of the leaf. These areas become dry and tear away, typically giving the foliage a ragged appearance. Often the leaves at the center of a plant are attacked first, leaving the stem and runners bare. These cankers can girdle the vine, causing death of the tissue beyond the lesion. Fruit, if infected early, may turn black, shrivel, and die.