Insecticide Evaluations for Soybean Aphid Management: the Good, the Bad and Their Residual Times

Soybean, Glycine max (L.), grown in Iowa and most of the north-central region of the United States has historically used low amounts of insecticide. However, an invasive insect pest has threatened soybean production in Iowa, with the arrival of the soybean aphid (Aphis glycines Matsumura). The soybean aphid causes yield losses from direct plant feeding, and has been shown to transmit several plant viruses. In Iowa, soybean aphid colonize soybean fields beginning in June and has produced outbreaks in July and August capable of reducing yields by nearly 25% (Johnson 2006)