Aphid population control is studied

U.S. agricultural scientists say farmers could save up to $12 per acre on insecticide treatments for soybean aphids by using the aphid's natural enemies.

Purdue University entomologist Bob O'Neil and colleagues at five other Midwestern universities found in most cases predators are able to consume enough aphids to keep aphid populations below crop-damaging levels.

"We built small screen cages and put soybean aphids inside them," O'Neil said. "There were similar numbers of soybean aphids outside the cage on plants. What we found was that the population size of soybean aphids inside the cage increased four times, whereas outside the cage aphid numbers typically decreased.

"Outside the cage, the natural predators (such as the Asian lady beetle and minute pirate bug) were reducing the aphid population," O'Neil explained. "When we protected the soybean aphids, those populations grew. That told us that these natural predators were important and that farmers need to pay attention to them."

The on-going research is a collaborative effort of Purdue, Iowa State and Michigan State universities, the universities of Illinois, Minnesota and Wisconsin; the Illinois Natural History Survey and the U.S. Department of Agriculture.

Copyright 2006 by United Press International