Anthracnose on melon.
Anthracnose on muskmelon.
Anthracnose on cucumber.
Anthracnose on watermelon.
Yellow, water-soaked areas spot melon and cucumber leaves, enlarge rapidly, and
turn brown and dry. These spots then shatter, leaving a ragged hole. On
watermelon leaves, the spots turn black. Elongated dark spots with light
centers may appear on the stems. Whole leaves and vines die. Large fruit is
spotted with sunken, dark brown, circular spots. Pinkish ooze may emerge from
the spots. Young fruit darkens, shrivels, and dies.
This plant disease is caused by a fungus (Colletotrichum lagenarium) and is the
most destructive disease of melons and cucumbers in the eastern United States.
It rarely attacks squash and pumpkins. The disease affects all aboveground
parts of the plants, and is most prevalent in humid weather with frequent rain
and temperatures from 70' to 80' F. The spores overwinter in seeds and plant
debris not removed from the garden. Spores are spread by splashing water,
cucumber beetles, and tools.
At the first appearance of the disease, treat plants with a fungicide
containing chlorothalonil. Repeat every 7 days or more frequently if warm,
humid weather occurs. Grow varieties resistant to this disease.