Compatibility of soybean aphid integrated pest management strategies

The soybean aphid, Aphis glycines, is a major economic pest of Midwest soybean. Since its discovery in the United States in 2000, significant strides have been made in developing an integrated pest management (IPM) program for this pest. The primary method of controlling soybean aphid outbreaks is through the use of foliar insecticides, but alternative management strategies such as host plant resistance varieties, reduced-risk insecticides and neonicotinoid seed treatments are also available. In addition, natural control from soybean aphid natural enemies can contribute towards aphid suppression. Conserving these natural enemies is an important component of soybean aphid IPM. The focus of this dissertation is to better understand the interactions between the management strategies currently available for soybean aphid management and whether the strategies are 1) effective at managing soybean aphid populations and 2) can successfully be utilized in combination with natural enemies to improve on soybean aphid IPM. To investigate these questions, both laboratory and field studies were conducted over three field seasons. Field studies demonstrated varying impacts of reduced-risk insecticides on the soybean aphid and its natural enemies. Minimal effects on soybean aphid and their natural enemies were demonstrated from the use of aphid resistant soybean and seed-treated soybean. Laboratory studies showed minimal non-target risks to natural enemies from exposure to seed treatments and host plant resistance. A field study to enhance aphid biological control with a buckwheat intercrop demonstrated minimal effects on either aphid or natural enemy populations. In summary, alternative soybean aphid management strategies exist that successfully suppress aphid population while also minimizing risks to natural enemies. Results of this research will help improve the integration of management strategies in soybean aphid IPM.