University of Illinois Extension
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Anthracnose on Leaves & Fruits of Cucumbers, Muskmelons and Tomatoes


Anthracnose is caused by a fungus, Colletotrichum orbiculare that attacks cucumbers, and melons as well as tomatoes and other vegetables. The symptoms begin as yellow spots or water soaked areas on the leaves or fruits. The attacked areas enlarge rapidly, turn brown and may form a ragged hole within the spot. The attacked fruits have brown, depressed water-soaked circular lesions, which turn black as the disease progress, and the fruit finally shrivels. The disease can attack fruit both in the field and in storage. The fungus overwinters in residues and seeds of attacked plants.


Plant resistant varieties when possible; plant certified pathogen-free seeds; avoid working among the plants when plant foliage is still wet; control volunteer cucurbits; follow a regular spray program with fungicides recommended in your state and follow pre-harvest interval; and bury deep any crop residues after harvest.