Farmers urged to take soybean aphids seriously

BY BRYCE KELLY

Mt. Pleasant News

For soybean farmers, insects are expected to be a nuisance every growing season. However, this year, soybean farmers are being warned on the dangers of early soybean aphid infestations that can quickly become more than just a nuisance.

?Typically, aphids are not as big of a problem in southern counties, whereas northern counties seem to deal with them more. However, this year, farmers are starting to notice them in larger numbers everywhere in Iowa,? says Erin Hodgson, an associate professor of entomology at Iowa State University. ?This year has been very conducive to aphid populations.?

Aphids, sometimes known as plant lice, are small sap-sucking insects that are often attracted to soybeans. These types of aphids are small (less than 1/16? in length), slow-moving, yellow-bodied and may be either winged or wingless.

Aphids prefer to feed on the undersides of leaves and tend to land on the newest leaves possible. One rather important feature of the lifecycle of a soybean aphid is the ability of the female to reproduce live, offspring during the summer months. This in turn allows for soybean aphid numbers to often increase rapidly when conditions are favorable in a soybean field.

A lover of moderate temperatures, aphids have thrived on the cooler summer Iowa has had this year, as opposed to past summers where temperatures soared to searing degrees. Hodgson also reports that infestations were being reported almost two weeks ahead of schedule compared to past years.

These tiny insects are among the most destructive pests on cultivated plants, and if left to their own devices, a large population of aphids can quickly dehydrate soybean plants. If a large colony develops, they will move to feeding on soybean plant stems. While initial infestations are typically patchy and located near a field?s edges, winged aphids can quickly disperse within and between fields.

?These pests are particularly damaging and have caused some lower yields already in fields across the state,? Hodgson says. ?So it?s important for farmers to be watching their fields closely this year.?

One characteristic that is commonly found in aphid infestations is the presence of ants on soybean stems and leaves. Groups of ants on soybean plants is often, but not always, an indicator of a soybean aphid infestation as the ants are attracted to the sweet sap the aphids produce while feeding.

ISU?s entomology department says appropriate pesticide use and habitual field checking is key to identifying or slowing an aphid infestation.

?Scouting and walking fields every seven to ten days is important in determining if you have major issues with aphids, or any pest for that matter,? Hodgson says. ?There is no way to guarantee a pest-free field, but taking some of these measures are important.?