The infestations appear to have occurred recently, as the aphids were only observed on leaves that had not yet expanded completely. The economic threshold for late vegetative through R5 stage soybeans is 250 aphids per plant with 80% of the plants infested and populations increasing.
The current economic threshold for soybean aphids is 250 aphids per plant with 80% of the plant infested and populations increasing. The article discusses the basis for this threshold and two scouting methods, including a speed scouting app, and management guidelines.
Confronting Crop Challenges will be the focus of five meetings to be held in northeast Nebraska this December. Each offers updates on recent crop and pest issues in eastern Nebraska as well as pesticide applicator recertification training.
Soybean aphid populations can explode in August under favorable conditions. Vigilant scouting is recommended, especially in northeast Nebraska where populations have historically been highest, to allow for timely management decisions.
Recommendations for scouting and managing soybean aphids, including why the 250-aphids-per-plant threshold is used. Two tools―an app and Excel worksheet―can help speed up scouting in the field and indicate when treatment is warranted.