Efficacy of Intercropping in Organic Soybeans for Management of the Soybean Aphid (2010)

Graduate Student Final Report – Ceres Trust Research Grant

Authors: Thelma Heidel – Graduate Student (Department of Entomology, University of Minnesota)

Professor: Dr. George Heimpel (Department of Entomology, University of Minnesota)

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Organic soybean producers lack effective management options for controlling the economically damaging soybean aphid, Aphis glycines Matsumura. Biological control by natural enemies is an important control measure in organic agricultural systems, and intercropping with flowering crops such as buckwheat can enhance biological control by attracting natural enemies. The purpose of this research project was to investigate whether intercropping organic soybeans with buckwheat can be an effective management option for suppressing soybean aphid populations. In 2010 field experiments were conducted at two locations in Minnesota to investigate 1) whether a soybean/buckwheat intercrop could effectively manage soybean aphid populations and 2) if so, whether natural enemy recruitment was a mechanism involved. Comparisons between intercropped plots and soybean-only plots showed slight differences between aphid and natural enemy numbers for both locations, however none of these differences were statistically significant. At Evansville, MN, intercropping demonstrated higher natural enemy populations, but whether this was due to natural enemy recruitment from buckwheat or a response to higher aphid densities is unclear.

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