Anthracnose

All you need to know about this fungal disease

Anthracnose is a fungal disease that afflicts leaves and tender shoots as they emerge in spring. The fungus also infects older leaves, producing large, irregular brown blotches. On tomatoes and peppers, small, circular, water-soaked spots appear on the fruit and grow in size, eventually penetrating and spoiling the fruit. Small branches may show twig dieback and cankers. Because symptoms vary depending on the plant, take a sample of the infected plant part to your Cooperative Extension Office or a full-service nursery for help in diagnosis.

Wet conditions encourage anthracnose fungi. If your area receives plentiful rainfall during the growing season, look for resistant plants. Grow vining plants on freestanding trellises or poles (well away from walls or fences) to keep them dry. Change from overhead to ground watering. Eliminate sources of future infection by pruning out all infected twigs and branches and raking up fallen infected leaves. Lime sulfur may prevent spores from attaching to plant parts.

For chemical control, you can use chlorothalonil in spring. Spray when leaves unfold, then two or three more times at 2-week intervals.