Plant Health Initiative

Soybean aphid - Agronomic impact

Signs of aphid feeding. Click on image to view a larger version. Photo credit: University of Wisconsin

Yield loss is related to the density of aphids at specific crop stages, and on the condition of the crop.  Risk of yield loss is greatest when aphid populations peak at beginning flower because of the impact on pod set.

Aphid populations tend to be higher and more damaging in fields or parts of fields where plants are already stressed from dry soil, soil fertility factors, weather conditions, other diseases, or in fields that are planted late. Scout such fields most closely.

Aphids can transmit soybean viruses

A separate issue from the direct damage caused by aphid feeding is the ability of soybean aphids to spread virus particles from plant to plant as they feed. Soybean mosaic virus and other viruses are spread by soybean aphids in the North Central region. Virus infection that occurs in early growth stages presents the greatest risk of yield loss and reduced seed quality, compared to infection later in the season.

 

Resources

Ecoonomic Impact of the Soybean Aphid - Integrated Plant Management newsletter, ISU