Hartman recommends that farmers should plant aphid-resistant varieties if they have experienced aphid problems in the past. In addition, farmers should closely monitor aphid populations in their fields and spray when populations reach the economic threshold level, approximately 250 aphids per plant. If farmers find threshold populations on resistant varieties, they should contact their local Extension agent.
Fortunately aphid infestations can easily be controlled with insecticides, Hill said. However the question of timing becomes a key factor that requires scouting of fields and entomologist recommendations regarding threshold levels. Hartman said farmers can save some of their yield if they follow guidelines found in U of I Extension literature.
"Soybean aphids have a closer relationship with their host than other bugs," Hill said. "They can feed on other plants, but they only readily reproduce during the summer months on soybean. They suck all of the life out of the plant in a matter of weeks, causing tremendous yield loss for farmers. This makes scouting crucial."
U of I researchers are continuing to look for new resistance genes while studying the genomics of the soybean aphid to better understand its virulence. Hill believes plant resistance can provide an effective, economical and sustainable method of insect control.
"We hope the use of molecular markers to identify biotypes will be available soon so we can take samples in the field and perform quick DNA tests to determine distribution of these biotypes," Hill said. "Our goal is to help the soybean seed industry determine where to market soybean varieties with particular soybean aphid resistance genes to ultimately help producers select a
|Contact: Jennifer Shike|
University of Illinois at Urbana-Champaign