Problem Identifier Unit Screen//v.w/ RR Template

Problem Identifier Unit Screen//v.w/ RR Template Fungal Leaf Spot

Problem
Spots and blotches appear on the leaves. The spots may be yellow, red, tan, gray, or brown. They range in size from barely visible to ¼ inch in diameter. Several spots may join together to form blotches. Leaves may be yellowing and dying. Leaf spotting is most severe in warm, humid weather.

Analysis
Begonias are susceptible to several fungi that cause leaf spots. Some of these fungi may eventually kill the plant, or weaken it so that it becomes susceptible to attack by other organisms. Others merely cause spotting that is unsightly but not harmful. These fungi are spread by splashing water, wind, insects, tools, and infected transplants and seed. They survive the winter in diseased plant debris. Some of the leaf spot organisms affect a large number of plants. Most of these fungi do their greatest damage during mild weather (50° to 85°F). Infection is favored by moist conditions.

Solution
Spray with a fungicide containing mancozeb at intervals of 7 to 10 days. Because leaf spots are favored by warm, humid conditions, it is important to spray frequently during these periods. This fungicide protects the new, healthy foliage. However, they will not eradicate the fungus on leaves that are already infected. Clean up and destroy infected leaves and debris.

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