This is Aaron Nygren, your local agronomist with Nebraska Extension in Colfax, Cuming, and Stanton counties. Last week, Wayne Ohnesorg covered some important information on soybean gall midge. This week I want to give you an updates since we just received confirmation from UNL researchers that soybean gall midge adults have started emerging in the area. Let’s recap what we know about soybean gall midge, how their emergence is being tracked, and go through some management options going forward.
If soybean gall midge doesn’t ring a bell, don’t worry as this insect has just recently started causing damage to area soybean fields. Symptoms of damage are dead or damaged plants on the outsides of fields, with damage usually worse directly bordering fields that were in soybeans the previous year. Plants develop discolored stems near the base of the ground and break off very easily. This damage is caused by the larvae stage of the insect, which are quite distinctive, with a bright orange color.
This spring, researchers at UNL and surrounding states established plots on fields planted to soybeans last year to track soybean gall midge emergence using corn rootworm emergence cages. These cages trap insects that emerge out of the soil into a mason jar for analysis. The first detection of emerged soybean gall midge were in Cass County on June 14th. During the last several days, additional midges have been found in Saunders, Stanton, and Cedar Counties. However, most of these sites have had very low numbers of midge emerge, so we will likely see numbers continue to build in the coming days or weeks. Numbers are being reported at UNL’s CropWatch website, found at cropwatch.unl.edu.
For management, we unfortunately do not as yet have research-based control recommendations. At this point, there are some preliminary recommendations based on midge observations. The main recommendation is that treatment is only advised for those that have soybean fields in areas where adjacent fields experienced significant economic losses last year. Applications of insecticides that provide residual activity control may be warranted to control as many emerging adults as possible. Ideally, applications could be made to just to the outside portions of soybean fields since that is where the majority of damage has been found in previous years. In areas where emergence numbers are low, growers may want to wait until higher numbers of midge are detected in traps to avoid having to reapply as numbers grow or risk being limited on when they can reapply based on insecticide labels.
So to recap, soybean gall midge have started to emerge at several locations across the area so stay tuned to cropwatch.unl.edu for updates on trap counts and management recommendations.
To listen to this radio message again or to get more information, visit our local website at croptechcafe.org or give me a call at 352-3821. This is Aaron Nygren, your local agronomist for Nebraska Extension on KTIC radio.
