Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2003
Publication Date: 2/1/2004
Citation: Liu, J., Wu, K., Hopper, K.R., Zhao, K. 2004. Population dynamics of aphis glycines and its natural enemies in soybean in northern china. Annals of the Entomological Society of America. 97(2):235-9 Interpretive Summary: Soybean aphid is a major pest of soybean which has recently invaded the United States, putting whole regions of soybean production at risk. As part of an effort to find predators and parasites of this aphid that might be useful for its control, we did field research in China. We found 12 predatory and parasitic insects attacking soybean aphid and showed that these insects kept the aphid below levels needed for insecticide treatment in China. This results indicate that it may be possible to use biological control to manage this pest.
Technical Abstract: A field survey of soybean aphid, Aphis glycines, and its natural enemies was conducted during the summer of 2002 in Langfang of northern China (116.4oE, 39.3oN). Aphids colonized soybean when plants were still small in early July. After a lag of two weeks, aphid density increased rapidly in late July, reaching a peak of 114±46 aphids per 5 soybean plants on 1 August. The population declined to a plateau immediately after this peak, and then declined again starting in mid August, although a second small peak occurred in late August. The finite rate of increase varied from zero to 5-fold, and the aphid appeared to be limited by natural enemies. The main species of natural enemy were the aphid parasitoid Lysiphlebus sp. (Hymenoptera: Braconidae), the aphid predators Propylaea japonica (Thunberg), Scymnus (Neopullus) babai Sasaji (Coleoptera: Coccinellidae), and Paragus tibialis (Fallén) (Diptera: Syrphidae). In a field exclosure experiment, Aphis glycines density in small-mesh (1 x 1 mm) cages peaked 3-fold higher in the large-mesh (2 x 2 mm) cages and 12-fold higher than on uncaged plants, indicating that natural enemies did indeed limit aphid density.