Early season insects can feed on soybean seeds and seedlings causing plant injury, stunting, delayed emergence, or stand loss. Scouting is necessary to determine the types of insects present and their population densities in order to make informed management decisions. Sampling methods include visual counts, soil sampling, and using baited traps.
What to look for in the field?
Preventative treatments, like seed treatments, may be available to help provide above ground protection from early season BLB and SBA for up to 30 days after planting. After emergence, scouting can help determine if action thresholds are met and insecticide application is warranted. However, treatment action thresholds (Table 1) can vary by state, pest, and stage of crop development. Consult with an Extension entomologist and/or agronomist for local recommendation.
Table 1. Treatment recommendations and action thresholds for early season soybean insects.
1 Boyd, M. L. and W. C. Bailey. 2000. Soybean pest management: Bean leaf beetle. G7150. University of Missouri Extension. https://extension.missouri.edu/publications/g7150
2 DiFonzo, C. 2009. Heavy soybean aphid infestations on early-season soybeans. Michigan State University. https://www.canr.msu.edu/fieldcropsent/uploads/files/14EarlySeasonSBA.pdf
3 Field Crops IPM. 2009. Purdue University. https://extension.entm.purdue.edu/fieldcropsipm/
4 Koch, R., and B. Potter. 2018. Early season scouting for soybean aphid. University of Minnesota Extension. https://extension.umn.edu/soybean-pest-management/scouting-soybean-aphid
5 Scout info. University of Kentucky. Kentucky IPM Pest Information Pages.
6 Soybean insects guide. 2011. Iowa State University. https://www.ent.iastate.edu/soybean-insects-guide