Remedy for Septoria Leaf Spot

Symptoms

• Symptoms appear within five days of infection. The disease starts with small, black or dark-brown, round spots on the leaves. The spots soon multiple and grow, showing a lighter-tan center with dark-brown edges. The leaf then turns yellow to brown, dries and falls from the plant. The fungus generally starts with the older leaves and moves to the younger leaves. Warm, wet, humid conditions promote the fungus.

Sanitation

• Septoria leaf spot fungus spores exist on infected debris left to decompose in the surrounding soil and in compost piles. Remove dead, dying plant material from your garden, and not work it into the planting ground at the end of the growing season. Rotating your tomato planting to new locations from year to year also decreases infection. When infected leaves are discovered, carefully remove the diseased leaves from the plant and dispose of them.

Care

• Even if your garden soil contains the spores of septoria leaf spot fungus, proper care eliminated the possibility of the disease infecting your plant leaves. Septoria leaf spot becomes active when temperatures are between 60 and 85 degrees Fahrenheit combined with high moisture. Avoid overhead watering of your plants. Using ground irrigation instead avoids water splashing on the leaves. Space the plants so that air freely circulates, drying the leaves. Remove all fallen plant debris around the plants and remove infected leaves from the plant. A thick layer of clean bark mulch around the plants and over the soil helps prevent the spores from reaching the leaves.

Fungicide

• Early application of a commercial fungicide formulated to control septoria leaf spot should be applied at the first sign of the disease. Applying a fungicide spray early in the growing season by mid-June can protect your plants from future infection. Follow the directions on the fungicide and apply the fungicide on all parts of the plant, including the underside of leaves, until the fungicide runs off. In warm, wet weather, reapply the fungicide every seven to 10 days. Frequently examine the plant leaves for septoria leaf spot infections and quickly take action to eliminate the fungus.