We haven't had much to report about soybean aphids this season, but they still bear watching. Kevin Black, with Growmark in Bloomington, reported that densities of soybean aphids in the Lake Geneva area in Wisconsin were high enough to warrant insecticide application recently. Populations of soybean aphids in Illinois have been small thus far in 2001, but as we have stated in the past, their numbers can build rapidly.|
Steve Doench, agronomist with Pioneer Hi-Bred International, found soybean aphids in Bureau and Lee counties on July 10. He found 10 to 20 aphids per plant, mostly on new trifoliate leaves. Gray Bretthauer, Extension unit educator in crop systems in Kendall County, indicated he had to look pretty hard to find the aphids. He usually finds them by looking for lady beetles and ants on the soybean plants. He reported that densities in his area this year are far lower than they have been during the past 2 years.
At this time, I can't offer much more than to say, "Keep scouting for soybean aphids." The hot, dry weather may be discouraging population growth. We'll keep our eyes on developments in the northern states (Michigan, Minnesota, and Wisconsin) and share the information we gather.--Kevin Steffey