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

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

Problem
Leaves are mottled yellow and green, and may be longer and narrower than usual, and puckered. Raised dark areas develop along the central vein, and the leaf margins curl downward. The whole plant is stunted. Pods on the affected plants may be faded, rough, and few in number. The seeds inside are shriveled and small. The damage is most noticeable when the temperature is between 60° and 75°F.

Analysis
Bean common mosaic and bean yellow mosaic are widespread virus diseases. Common mosaic virus affects only French and snap beans; yellow mosaic virus affects lima beans, peas, summer squash, clover, gladiolus, and other perennial flowers. Both diseases are spread by aphids, which transmit the virus as they feed. (For more information on aphids, see Aphids.) In warmer parts of the country with large aphid populations, the disease spreads rapidly. Common bean mosaic is also spread in infected seed. If the infection occurs early in the season when the plants are young, the plants may not bear pods. Infection later in the season does not affect pod production as severely. For more information on virus diseases, see Virus Diseases.

Solution
There are no chemical controls for plant viruses. To reduce the aphid population and the spread of disease, apply an insecticide containing malathion or diazinon, or an insecticidal soap as soon as the first insects appear. Remove all infected plants and all clover plants in the vicinity of the garden. Plant virus-resistant varieties of beans listed in Beans Resistant to Mosaic.

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