The current economic threshold for soybean aphids states that an insecticide application is warranted when soybean aphid densities reach 250 soybean aphids per plant, 80% of sampled plants are infested, the population is currently increasing, and few natural enemies are observed in the field. This recommendation is only valid from the R1 (beginning bloom) to R5 (beginning seed) growth stages and is based on an economic injury level of 674 soybean aphids per plant. Due to the clumped spatial distribution of soybean aphids, Onstad et al. (2005) recommend that 50 plants should be sampled within a field to attain an accurate representation of densities of soybean aphids. Soybean producers can choose from a variety of foliar insecticides from the carbamate, pyrethroid, and organophosphate chemical families to control soybean aphids.
