Inspecting for insects - the importance of scouting in soybean fields

Published on: 14:20PM Jan 25, 2011

Dr. Roy Boykin

With every new year comes a new opportunity for a successful growing season. To make the most of that opportunity, it is important to be aware of the pests that will be working against your plans for record-breaking yield. Each year, soybean yields are threatened by various insect pests that can cause significant damage and yield loss. Insect pests like soybean aphid, bean leaf beetle and stinkbugs are just a few of the pests that can quickly take over fields and reduce crop yields and quality as well as profits. For this reason, it is crucial for soybean growers to regularly scout and properly identify these destructive insects.Soybean aphid 

Soybean aphids have quickly become one of the greatest potential threats to soybean fields. An infested field can suffer yield losses up to 50 percent if the infestation goes untreated. According to the Iowa State University Extension, soybean aphid populations can double in just two to three days if conditions are favorable, making early scouting a critical step in protecting your yield.

Soybean aphid

Another common insect is the bean leaf beetle that, like the aphid, can reduce yields by 20-50 percent if left unmanaged. Bean leaf beetleThese pests damage soybean plants by feeding on the foliage and the base of the pods, which causes defoliation and reduced seed quality. Entomologists from Iowa State University Extension recommend that scouting should begin during the R4 growth stage and continue through the R7 stage.

Bean leaf beetle 

The stinkbug is a pod and seed-feeding insect that can lead to reduced seed quality and quantity. StinkbugIn young seeds, stinkbug feeding can result in undersized or aborted seeds, whereas older seeds will become discolored and shriveled, reducing germination rates. The University of Missouri Extension recommends beginning to scout for stinkbugs once soybean plants start to bloom since female stinkbugs are highly attracted to the blooming soybean plant. Peak populations are typically found in August to September.


Knowing how to identify and scout for these insects is half the battle. It is important to have a plan of action to stop an insect infestation as well. An insecticide with dual modes of action, a fast knockdown and long residual can prevent populations of hard-to-control insects, like the soybean aphid, bean leaf beetle or stinkbug, from damaging your fields and give your soybean maximum opportunity for a successful yield.

What insects are you most worried about this upcoming season?

Dr. Roy Boykin, Senior Technical Brand Manager, Insecticides, Syngenta Crop Protection 
Roy is responsible for the technical development, positioning and product life cycle management of insecticides for all business units in the NAFTA Region. Roy received his undergraduate education at the College of Charleston with majors in biology and business and received his master’s/doctorate degrees in entomology with minors in plant pathology and crop science from North Carolina State University.