Soybean aphid management in Iowa; the importance of planting date, seed treatments and thresholds
Kevin Dennis Johnson, email@example.com, Matt E. O'Neal, firstname.lastname@example.org, Jeffrey D. Bradshaw, email@example.com, and Marlin E. Rice, firstname.lastname@example.org. Iowa State University, Department of Entomology, Ames, IA
Soybean aphid, Aphis glycines Matsumura (Homoptera: Aphididae) was first reported in Iowa in 2000 and by 2003 was found in every county with the heaviest populations reported in the northwest corner of the state. During the 2003 growing season, soybean aphid populations reached the highest yet reported for Iowa resulting in nearly 4 million acres treated with insecticide. Although a preliminary scouting and threshold are available, many questions still remain regarding soybean aphid management. Our goal for 2004 is to address the compatibility of current soybean pest management programs used in Iowa and participate in a regional study to refine preliminary recommendations.
Our specific objectives test several management techniques in replicated block experiments at three locations in Iowa. The first objective is to characterize the effect of planting date on soybean aphid and bean leaf beetle management. The second objective is to determine the importance of spray coverage on soybean aphid mortality. And finally, we will compare the effectiveness of prophylactic treatments (seed treatments and an insecticide applied with a post emergent herbicide) to a soybean aphid management programmed based on weekly scouting and a set threshold of 250 aphids per plant.
Key word: IPM, soybean aphid, seed treatments, planting date