Soybean aphids can infest soybean plants, causing yellowing, distorted leaves and stunted plants. These insects like to stay on the top of the plants on the newest growth, especially in the folded leaf that hasn't emerged yet.
In Michigan, soybean aphids overwinter on buckthorn trees, and after one to two generations, the winged aphids come out and colonize soybeans. Since soybeans in most of Michigan came up later this year, Michigan State University Extension entomologist Christina DiFonzo believes that in 2019, soybeans emerged after the soybean aphids moved off the buckthorn trees and for this reason they did not get colonized yet. Later in the year, there is a possibility that soybean fields will get colonized, mostly by aphids coming from neighboring fields or even from Minnesota or Wisconsin.
You should be using the threshold of 250 soybean aphids per soybean plant when scouting your fields. Aphids’ presence about the threshold levels would indicate that an insecticide application might be beneficial. An infestation situation that you would need to spray would be when the plant is covered with bright green aphids.
Based on DiFonzo’s experience, spraying pesticides when an infestation occurs early in the season doesn't pay off. Even whre there are 50-100 aphids per plant, biocontrol agents such as ladybugs and lacewings can do a good job controlling soybean aphids.
If you are interested in learning more about this topic, watch this short video.
Source: Michigan State University
The source is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.