If a soybean aphids could talk, I would imagine them screaming, " Stop touching me!". Many Iowan fields are infested with soybean aphid this summer. Erin and Matt talk about what to do when these increasing populations happen late in the season. A short conversation about aphids in corn also happens. Finally, they get diverted and talk about winged aphid formation based on several cues, like touching and predators.
The podcast took a break while Matt was on vacation and Erin was on the extension circuit. But they're back and talking about recent pest activity in Iowa. First, Erin shares updates about treating for soybean aphid in northern Iowa. Populations were erratic, as usual, and some fields exceeded threshold in early- to mid-August. A few people noticed poor performance of bifenthrin, a pyrethroid, for soybean aphid. This isn't a huge surprise, given there are pyrethroid-resistant populations in southwestern and southcentral Minnesota in 2015 and 2016. It is important to assess insecticide efficacy and determine potential issues with soybean aphid. In general, soybean are approaching mid- to full seed set throughout Iowa and yield responses are not consistent when applied after full seed set.
In addition, Erin has noted some corn fields with abundant aphid populations. Some fields exceeded 1,000s per plant and were treated with aerial applications last week and this week. Economic thresholds for these pests are not well defined, but Erin has an ICM News article to take into consideration.
Matt and Erin will be at the 2016 Farm Progress Show near Boone, Iowa on August 30. Erin will be at the ISU Event Tent in the morning and have a presentation at 10am. Matt will be there in the afternoon - so stop by and see them!