As soybean fields enter seed set, growers are getting concerned about late-season soybean aphid infestations. And with good reason - winged aphids are everywhere and some areas are experiencing increasing aphid densities. There is much evidence to show treating aphids when they exceed the economic threshold (250 aphids per plant with increasing populations on 80 percent of the plants) up to R5.5 will protect yield. But what happens if aphid populations are still increasing past seed set? This was the trend in 2008 when aphid populations were still increasing into September. So do late season insecticides financially make sense for managing soybean aphid? This is a difficult topic for us to discuss because of the lack of replicated data throughout the North Central Region.
Iowa State University
Hodgson, Erin W. and O'Neal, Matthew E., "Are Late-Season Soybean Aphid Treatments Worth It?" (2009). Integrated Crop Management News. 560.
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