Biological Control of the Soybean AphidEPA Grant Number: F6F21357
Title: Biological Control of the Soybean Aphid
Investigators: Chacon, Jeremy
Institution: University of Minnesota - Twin Cities
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2006 through September 1, 2009
Project Amount: $111,172
RFA: STAR Graduate Fellowships (2006) RFA Text | Recipients Lists
Research Category: Fellowship - Entomology , Academic Fellowships , Biology/Life Sciences
The primary objective of this research is to determine how potential classical biological control agents of the soybean aphid (Aphis glycines) will interact with resident natural enemies in the field, and how these interactions (called intraguild predation) will affect the strength of biological control. Additionally, this research will try to determine why parasitoid wasps are apparently crucial to natural biological control of the soybean aphid in its native range, and seemingly unimportant in North America, where soybean aphid is invasive. The culmination of this research will be a decision of what, if any, classical biological control agents should be released against the soybean aphid and the determination of the importance of intraguild predation studies on pre-release trials of classical biological control agents.
The objectives of this research will be met through a series of manipulative field experiments, quarantined laboratory experiments, and molecular gut-contents analyses. To determine how a classical biological control agent may interact with resident natural enemies, a model parasitoid (Aphidius colemani) will be used in factorial field experiments examining the effects of varying start densities of soybean aphid, parasitoid wasps, and natural enemies on soybean aphid growth rates in Minnesota. Subsequent molecular gut-content analyses will be performed on collected predators from these experiments to determine which predator species engage in intraguild predation against the parasitoid wasp, and at what frequencies. Quarantined laboratory experiments using proposed biological control agents of the soybean aphid and individual natural enemy species will be performed to determine the strength of intraguild interactions between specific predator species and the proposed agents, and the effect of these interactions on control of the soybean aphid. Finally, factorial field experiments using cages to exclude predators and/or parasitoids will be conducted in soybean aphid’s native range, to determine why intraguild predation does not appear to be an important influence on natural biological control of the soybean aphid there.
The manipulative field experiments will help to elucidate if classical biological control of the soybean aphid using a parasitoid wasp is likely to be effective, and how intraguild predation against the parasitoid wasp will affect this control. The molecular gut-content analyses, combined with the quarantined laboratory studies, will determine which predators are the most important intraguild-predators, and will also determine if certain classical biological control agents are less prone to intraguild predation than others. This knowledge will allow us to choose whether or not to release a biological control agent against the soybean aphid, and help us choose which proposed agent has the greatest potential.