Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/2007
Publication Date: 8/20/2007
Citation: Miao, J., Wu, K., Hopper, K.R., Li, G. 2007. Population dynamics of APHIS GLYCINES (Hompotera: Aphididae) and impact of natural enemies in northern China. Environmental Entomology. 36:840-848. Interpretive Summary: Soybean aphid is a major pest of soybean which invaded the United States in 2000, 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 continued field research begun in 2002 in China in 2003-2004. We found 19 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: As part of a project on biological control of the soybean aphid, APHIS GLYCINES, field surveys of this aphid and its natural enemies, as well as natural enemy exclosure experiments, were conducted during 2003 and 2004 in soybean fields near Langfang, China. In 2003, aphid density increased 6-fold during 12 days in July from a low of 66 per ten plants to a seasonal peak of 401 per ten plants. Aphid density remained high for another 10 days and then declined during early August. In 2004, aphid density increased 29-fold during 13 days in July from a low of 14 per ten plants to a seasonal peak of 375 per ten plants. Unlike 2003, aphid density remained relatively high during late July and August, peaking again at 296 per ten plants on 24 August. In both years, aphid density remained below the economic injury level and appeared to be limited by natural enemies. Exclosure of natural enemies led to increases in A. GLYCINES density in 2003 and 2004. In 2003, peak aphid densities in large and medium-mesh cages were 3-fold and 7-fold higher, respectively, than densities on uncaged plants. In 2004, peak aphid densities in large and medium-mesh cages were 2-fold and 30-fold higher, respectively, than densities on uncaged plants in one experimen. In another experiment, peak aphid densities in large, medium, and small-mesh cages were 8-fold, 28-fold, and 68-fold higher, respectively, than densities on uncaged plants. Both predators and parasitoids were important in limiting aphid density. We compare our results with similar experiments in North America and discuss the implications for biological control of soybean aphid.