UW Soybean Plant Health
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Rugosity (rough leaves) is a symptom of virus infection. Photo © Palle Pedersen, ISU |
Agronomic Impact
Our experience over the past few years suggest that SMV does not generally affect yields. The major concern about this disease is seed quality.
However, soybean plants are commonly infected with more than one virus, which increases risk of yield loss and lower seed quality. SMV and AMV often occur together in the same plant. Tobacco streak virus and Bean pod mottle virus (BPMV) have also been found in multiple infections.
Management of Soybean Mosaic Virus
Infected seed is the most important way that soybean mosaic virus is introduced into a soybean field. The virus is rarely found in plants other than soybean, and therefore aphids are not likely to acquire the virus outside the soybean field. Planting SMV-free seed is an effective way of preventing the disease.
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| Lower populations of aphids usually observed on early-planted soybean fields. Click on graph to view larger version. Data from Craig Grau, UW-Madison, 2002. |
Once established in a field, aphid vectors spread the virus when feeding. Research is in progress to determine whether management practices can modify aphid activity and transmission of SMV. Late planting coincides with higher populations of the soybean aphid and increases the probability of transmission to young seedlings. Infection in the early growth stages has the greatest risk of yield loss and reduced seed quality, compared to infection later in the season.
Insecticides are not considered effective in reducing transmission of SMV by aphids. Aphids present at spraying are killed, but the field is quickly recolonized by winged aphids and virus transmission can resume. Aphids that contact insecticide residues on the leaf surface are killed, but are capable of virus transmission prior to death.
Most commercial soybean varieties are susceptible to SMV. However, partial resistance to SMV has been identified in soybean genotypes and variety testing for virus resistance is continuing in our research trials. Maintain a dense soybean canopy.
Read more about the soybean aphid in Wisconsin »
Read how researchers work with viruses»
Information from this site can be copied and distributed for educational use. Please credit the source with our name and URL: University of Wisconsin-Madison, Departments of Agronomy, Entomology, and Plant Pathology at www.plantpath.wisc.edu/soyhealth.
Last update 4/4/06