- Agronomic: soybeans
- Additional Plants: herbs, native plants, trees
- Crop Production: biological inoculants, continuous cropping, double cropping, multiple cropping
- Education and Training: on-farm/ranch research
- Energy: bioenergy and biofuels
- Pest Management: biological control, cultural control, integrated pest management
- Production Systems: agroecosystems, organic agriculture
In experiments conducted over the 2014-2016 field season at the U of MN Agricultural Experiment Stations in Rosemount and St Paul, MN, and in two farmer’s fields in Northfield and Cottonwood counties, we evaluated introductions of the Asian parasitoid Aphelinus glycinis in the presence and absence of prairie vegetation and also evaluated the effectiveness of the resident Asian parasitoid Aphelinus certus at the St. Paul site.
Our results showed that A. glycinis could establish well during the field season but we could not confirm successful overwintering of this species although limited overwintering was found in an experiment conducted in 2014 (but not 2015). Further overwintering studies are in progress. Prairie vegetation did not have a significant positive or negative effect on soybean aphid parasitism by this other parasitoid species in our studies. However, the diversity of parasitoid species was higher adjacent to prairie species.
Parallel studies on the resident Asian parasitoid A. certus conducted in St. Paul during 2015 showed that this species was able to maintain soybean aphid at population densities below the economic spray threshold. Different studies in 2016 showed that both A. certus and A. glycinis species was negatively effected by neonicotinoid seed treatments. A study investigating the compatibility of both of these species and aphid-resistant soybean varieties in 2016 is currently being analyzed.
The soybean aphid, Aphis glycines, is the key pest of soybeans in the North Central U.S. We have been studying the effect of Asian parasitoids on soybean aphid pressure for the last decade and recently obtained permission from the USDA to release a specialized soybean aphid parasitoid known as Aphelinus glycinis against the soybean aphid in Minnesota. Simultaneously we have been studying the effect of native prairie plantings on biological control of soybean aphid by resident predators and parasitoids. In this research project we conducted releases of A. glycinis adjacent to these prairie plantings and compared resulting parasitism rates to control sites without prairie plantings. We also conducted releases of A. glycinis on two organic farms in Minnesota during the course of the study.
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We conducted releases of A. glycinis during the summers of 2014, 2015 and 2016 at 2 experiment station sites and 2 farmer’s fields. We also conducted overwintering studies on this species over the 2014/2015 and 2015/2016 winters with a third round of studies in progress. During the summer of 2015 we conducted releases of A. glycinis adjacent to prairie vegetation and compared these releases to ones conducted at control sites that were within monoculture soybean fields.