Anthracnose: Colletotrichum lindemuthianum
Symptoms
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Bean pods with black, sunken lesions or reddish-brown blotches most likely have anthracnose, a fungal disease caused by Colletotrichum lindemuthianum.
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Black, sunken lesions about ½ inch in diameter develop on stems, pods and seedling leaves (cotyledons) but are most prominent on pods.
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A salmon-colored ooze on lesions and the veins on lower leaf surfaces turns black. On lima beans, symptoms are sooty- appearing spots on leaves and pods.
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Anthracnose develops primarily during the spring and fall when the weather is cool and wet, and not during our hot, dry summers. Lima beans are particularly susceptible.
Management
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Prevent this disease by using certified disease-free seed for planting and removing all plant debris after harvest.
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Anthrac-nose can survive in the soil for two years on plant debris or be brought to the garden on infected seeds.
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Do not plant bean seeds in an area that had disease for two to three years. Avoid overhead watering and avoid splashing soil onto the plants when watering.
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Fungicide sprays of fixed copper are the only recommended chemical that can be used on lima beans for anthracnose control.
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