If you planted beans in fall as a cover crop, or in spring as a food crop, you may notice a problem with leaves looking pale, splotchy, and generally unhealthy. Blotchy, puckered bean leaves may indicate a bean mosaic virus.
There are three mosaic viruses in the Bay Area that attack beans:
Vectors of infection
Bean mosaic is spread by aphids, mealybugs, and leafhoppers. While it sounds convenient, research has shown that using insecticides is not practical because it kills the beneficial insects who would normally feed on the pests. Once a plant is infected, it becomes a vector for disease, as well, and should be completely removed from the site. Infected plants should not be added to the compost pile.
Controlling bean mosaic
Prevention is the best protection when it comes to bean mosaic. Use these handy tips to reduce the likelihood of future generations of beans becoming infected:
Bean mosaic is one of the most powerful arguments against using dried beans from the grocery store to plant in your garden. While they are perfectly safe to eat, there is no guarantee that they are safe to sow. Invest in high quality, guaranteed clean seeds from a reputable seller and then save the best seeds from your crop for replanting.
Beans are easy to grow. They improve soil structure, provide excellent food crops, and can look lovely in a landscape, as long as they are kept healthy.
I hope this information inspires you to grow more of your own food. You can ask your garden questions on my Home page.