Janet J. Knodel
Extension Entomologist
Soybean Aphids
The IPM Crop Scouts surveyed 92 soybean fields last week and soybean aphids were observed in only 9% of the fields surveyed. Soybean aphids continue to be detected at low densities ranging from 0 to 16 aphids per plant; however, incidence (% of plants infested in field) increased. The high was 86% incidence in three of the positive fields. Surveyed field were in the V5 to R3 (beginning pod) crop stages. With moderate temperatures (high 70sF to low 80sF), conditions are optimal for aphid reproduction and populations can double in only 3 days in the field. So, continue to scout for soybean aphids through the R5 (beginning seed) crop stage.
Beneficial insects that eat soybean aphids also have been increasing. Ladybeetles, syrphid fly larvae and lacewing larvae have been observed in fields infested with soybean aphids. Remember to avoid early insecticide applications, since insecticides kill beneficial predators and parasites.
Source : ndsu.edu