Clover yellow vein virus is a serious viral plant disease that is spread by aphids and infects beans, peas and other legumes, as well as cucurbits (cucumbers and squash). The leaves of the affected plant turn yellow and wither, and the plant eventually dies. Plant diseases like this are difficult to treat, and are best thwarted through prevention and good gardening practices.
Purchase disease-resistant plants and seeds. Seed packets and plants are usually marked disease-resistant, but consult a nursery expert if in doubt.
Spray aphids off plants with a spray bottle filled with water. Check on the undersides of leaves where aphids lurk.
Pull up any infected plants immediately. Throw them away; don't compost them. Composting infected plants spreads disease.
Water plants in the morning in warm, humid climates, or use soaker hoses so leaves dry quickly. Wet leaves contribute to the spread of clover yellow vein disease.
Clean up all garden debris in the fall. Compost or discard it to discourage yellow vein disease from overwintering in the soil.
Lay 2 inches of compost and 2 inches of moistened peat moss on the vegetable garden annually in the fall. Till it under by hand or with a rototiller. Healthy soil with plenty of organic material discourages pests.
Rotate crops annually so peas, beans and cucumbers don't grow in the same place. This enriches the soil and prevents vein disease from building up.
Introduce beneficial insects such as ladybugs and lacewing larva to your garden. These eat disease-spreading aphids and are available at nurseries.