When green bean plants begin to turn yellow, it is often a sign of disease. Identifying the cause of the yellowing is one way for gardeners to begin to fight it and restore the green bean plants to health.
Bean Yellow Mosaic Virus
The bean yellow mosaic virus is the most common cause of yellowing green bean plants. The virus is transmitted by aphids infected with the virus. Once the aphids begin feeding, the green bean plants can become infected.
Green bean plants infected by the yellow mosaic virus are unlikely to survive. The University of California recommends planting varieties of the green bean that are resistant to the disease. Additionally, planting green beans away from perennials like clover can lower the likelihood of infection.
Another cause of yellowing green bean plants can be excess watering. If the roots of a green bean plant become waterlogged, the plant can turn yellow and begin to droop as it drowns. Regulating the amount of watering can help.