Predators and alate immigration influence the season-long dynamics of soybean aphid (Hemiptera: Aphididae)

Publication date: February 2018 Source:Biological Control, Volume 117 Author(s): J.A. Bannerman, B.P. McCornack, D.W. Ragsdale, N. Koper, A.C. Costamagna The identification of key species within multi-predator assemblages suppressing agricultural pests is paramount to the incorporation of predators into pest management plans. Generalist predators have strong impacts on population growth of soybean aphids (Aphis glycines, Hemiptera: Aphididae) in North America, but their relative influence may vary seasonally, and potentially interact with immigration of alate aphids following initial field colonization. Here we present the results of a season-long study in Minnesota that used cage manipulations to estimate weekly impacts of predation on field populations of soybean aphids, while concurrently quantifying alate aphid and predator densities. We used generalized linear models based on field level aphid and predator counts, and aphid counts on caged and uncaged experimental plants, to show that Harmonia axyridis (Coleoptera: Coccinellidae) was negatively associated with A. glycines abundance, even under alate immigration levels associated with aphid outbreaks, suggesting potential regulation of aphid populations. In contrast, two other common predators, Coccinella septempunctata (Coleoptera: Coccinellidae) and Orius insidiosus (Hemiptera: Anthocoridae), did not show patterns of association with aphid dynamics. We also show that A. glycines populations only have significant ...

Source: Biological Control - December 26, 2017 Category: Biology Source Type: research