Soybean Aphids Management

Virgil Schmitt, crops field specialist

Situation
In late summer 2003, large portions of eastern and southeastern Iowa experienced high numbers of soybean aphids. Because this portion of Iowa is close to neighboring states, information from other universities and from industry sources was available. Conflicting information resulted in much confusion about soybean aphid thresholds at various stages of soybean maturity, as well as confusion about insecticide selection.

Response
A four-state (Illinois, Iowa, Minnesota, and Wisconsin) videoconference was scheduled, in which researchers and extension specialists from each state shared research results and general observations about what worked and what did not. The culmination was a consistent set of guidelines for soybean aphid management, which was agreed upon by the land-grant universities in the upper mid-west. There were 11 sites for the video program in Iowa, including sites in Burlington and DeWitt.

Impact
Thirty-nine dealers and producers attended the videoconference in DeWitt, and 21 attended in Burlington. The attendees were asked how many soybean acres they scouted or managed in 2003 and what the estimated increased profit per acre would have been had the information from the meeting been available on August 1, 2003. While not all attendees returned an evaluation, respondents in DeWitt responsible for 219,600 acres of soybeans estimated that the improved profits would have been $27 per acre, or a total of $5,930,000. Respondents in Burlington responsible for 77,300 acres of soybeans estimated that the improved profits would have been $32.34 per acre, or a total of $2,499,500. Although we hope not to see a repetition of the 2003 problems with soybean aphid soon, the information gathered should have a comparable impact on profits in the future.

Page maintained by Linda Schultz, lschultz@iastate.edu