Symptoms of this fungal disease vary with the crop. Beans develop round, black, sunken spots on the pods and stems; on leaf undersides, veins turn black. When the fungus infects cucumbers and melons, the leaves develop yellow spots that dry up and flake away; spots on watermelon leaves are black. Infected fruits develop sunken areas with dark borders. On tomato plants, ripe fruit develops sunken spots with dark centers.
Anthracnose can also develop in other vegetable crops and in strawberries. Wind and wet weather fosters the spread of infection. Anthracnose overwinters in plant residues in the soil. It is an especially troublesome disease in hot, humid regions.Prevention and Control
- Plant resistant varieties such as Calypso cucumber and Charleston Gray watermelon.
- Different species of fungi cause anthracnose in different crops. Thus, if you had anthracnose on your tomatoes last year, there’s no harm in planting beans in that bed this year. It can be helpful to wait two years before replanting tomatoes in that bed, though.
- Use drip irrigation or soaker hoses rather than overhead watering. Avoid disturbing plant foliage when it’s wet.
- Harvest tomato and pepper fruits promptly and wash and dry them immediately to remove any fungal spores on the fruit surface.
- Clean up crop debris in fall.