Click on the links above to go to the Virus Diseases home page or the Soybean Disease Atlas home page.
University of Tennessee
Soybean mosaic is caused by soybean mosaic virus (SMV) and is the most widely distributed virus diseases of soybeans. It is spread by planting diseased seed and by at least 31 species of aphids.
Symptoms of SMV vary depending on the soybean cultivar, the age of the soybeans, the virus strain, and the temperature. Symptoms are most noticable under cool temperatures of 18 to 24C. When temperatures rise above 30C, leaf symptoms may be masked. The youngest and most rapidly growing leaves show the most severe symptoms.
The leaves of SMV infected plants are distorted and narrower than normal, and develop dark green swellings along the veins. Infected leaflets are puckered and curl down at the margin. Plants infected early in the season are stunted, with shortened petioles and internodes.
Diseased seed pods are often smaller, flattened, less pubescenct, and curved more acutely than pods of healthy plants. Infected seed are mottled brown or black, usually smaller than seeds from healthy plants, and germination may be reduced.