Larval Infestation of Soybean
In Nebraska, soybean gall midge larval (Figure 1) injury to soybean has been found in most areas where adult soybean gall midge activity occurred over the past two weeks. A lack of injury has been observed in late-planted soybean fields in Cass County, NE and a planting date study at the Eastern Nebraska Research and Extension Center near Mead, indicating that soybean plants that were V2 stage may not be susceptible to the first generation of soybean gall midge. Full evaluations on these studies will occur in the next week or two. Similar observations were made in northwestern Iowa by Erin Hodgson, extension entomologist, and Mitchell Helton, entomology Master’s student, at Iowa State University.
Soybean Gall Midge Adult Activity
Adult emergence of soybean gall midge has declined significantly in east-central Nebraska with no new adult collections from the Cass County in the last two days. Some low levels of emergence have been observed in Saunders County. Larval infestation of soybean in this area makes it unlikely that foliar insecticides will have any effect on soybean gall midge. A previous CropWatch article indicated that the window for management with foliar insecticides has ended.
In northeast Nebraska, larval infestation of soybean was observed in Stanton County, NE. This signals the closure of the treatment window to prevent infestations of the first generation of soybean gall midge.
Figure 2 shows the cumulative adult emergence of soybean gall midge as of June 28, 2019.
Scouting for Soybean Gall Midge Injury
For information on scouting for soybean gall midge injury and larvae, view the video at go.unl.edu/scoutsgm
For all the latest information on soybean gall midge, go to https://cropwatch.unl.edu/gallmidge.
