A nematode, fungus, and aphid interact via a shared host plant: implications for soybean management.

摘要

Soybean, Glycine max (L.) Merrill (Fabaceae), is an introduced crop to America and initially benefited from a small number of pests threatening its production. Since its rapid expansion in production beginning in the 1930 s, several pests have been introduced from the native range of soybean. Our knowledge of how these pests interact and the implications for management is limited. We examined how three common economic soybean pests, the nematode Heterodera glycines Ichinohe (Nematoda: Heteroderidae), the fungus Cadophora gregata Harrington & McNew (Incertae sedis), and the aphid Aphis glycines Matsumura (Hemiptera: Aphididae), interact on soybean cyst nematode-susceptible (SCN-S) and soybean cyst nematode-resistant cultivars carrying the PI 88788 resistance source (SCN-R). From 2008 to 2010, six soybean cultivars were infested with either a single pest or all three pests in combination in a micro-plot field experiment. Pest performance was measured in a 'single pest' treatment and compared with pest performance in the 'multiple pest' treatment, allowing us to measure the impact of SCN resistance and the presence of other soybean pests on each pest's performance. Performance of H. glycines (80% reduction in reproduction) and A. glycines (19.8% reduction in plant exposure) was reduced on SCN-R cultivars. Regardless of cultivar, the presence of multiple pests significantly decreased the performance of A. glycines, but significantly increased H. glycines performance. The presence of multiple pests decreased the performance of C. gregata on SCN-S soybean cultivars (20.6% reduction in disease rating).Digital Object Identifier http://dx.doi.org/10.1111/j.1570-7458.2012.01227.x