The reddish-brown lesions along the leaf veins are caused by a disease called anthracnose. The anthracnose fungus, Colletotrichum lindemuthianum, also causes pod spots that are circular with dark margins and a pinkish sticky center that contains the spores (reproductive structures) of the fungus. Spots may also appear black and sunken.
This disease is favored by cool, wet weather. Avoid wetting foliage when watering plants. Remove heavily infected leaves and pods. A fungicide can be used at seven- to 10-day intervals to prevent disease. Remove and destroy infected plants at the end of the season. Avoid saving seed from diseased plants to plant the next year. Plant only certified disease-free seed each year. Rotate your plantings; do not plant beans in areas that had the disease for two to three years. Contact your local Extension office for fungicide recommendations.
