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ARS Home » Northeast Area » Newark, Delaware » Beneficial Insects Introduction Research Unit » Research » Publications at this Location » Publication #356296

Research Project: Classical Biological Control of Insect Pests of Crops, Emphasizing Brown Marmorated Stink Bug, Spotted Wing Drosophila and Tarnished Plant Bug

Location: Beneficial Insects Introduction Research Unit

Title: Impact of the parasitoid Aphelinus certus on soybean aphid populations

item Kaser, Joseph
item HEIMPEL, GEORGE - University Of Minnesota

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/2018
Publication Date: 8/17/2018
Citation: Kaser, J.M., Heimpel, G.E. 2018. Impact of the parasitoid Aphelinus certus on soybean aphid populations. Biological Control. 127: 17-24. 10.1016/j.biocontro.2018.08.014.

Interpretive Summary: The soybean aphid is the most serious insect pest in US soybean fields. An introduced beneficial parasitoid that attacks the soybean aphid has recently spread throughout much of the soybean aphid range in North America, but it is unclear if it is significantly reducing the soybean aphid's population. We conducted a study to estimate the impact of the parasitoid on soybean aphids in Minnesota. We found that the parasitoid can significantly reduce soybean aphid population growth, and it is likely contributing to reduced insecticide use for farmers. This work will help to inform researchers who study soybean aphid management and biological control, as well as help growers who practice integrated pest management.

Technical Abstract: Aphelinus certus Yasnosh (Hymenoptera: Aphelinidae) is an accidentally introduced parasitoid of the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae) in North America and it has become one of the most common natural enemies of soybean aphids in its adventive range. It is unclear, however, if increased prevalence of A. certus has resulted in increased biological control. We conducted an exclusion-cage experiment designed to isolate the impact of parasitoids from that of other resident natural enemies (mainly predators) of the soybean aphid. We found that A. certus greatly outnumbered all other soybean aphid parasitoids, and that it significantly reduced soybean aphid populations over a time span of less than two weeks compared to controls. Moreover, parasitoids alone resulted in aphid densities that were statistically equivalent to the combined effect of predators and parasitoids. Across all treatment cages, there was a significant negative association between parasitism rate and aphid population growth, with predicted zero aphid growth occurring at a parasitism rate of 44.2%.