Field Crops IPM Podcast: Soybean gall midge, spider mites, and corn rootworm in southern Minnesota

 Welcome to the 3rd IPM Podcast for Field Crops of 2020. Subscribe to the podcast and never miss an episode on iTunes, Google Podcasts, and Spotify.

This Podcast is sponsored by the UMN Extension Integrated Pest Management (IPM) Program. In this week’s podcast, we feature Bruce Potter, University of Minnesota Extension IPM Specialist based out of the Southwest Research and Outreach Center in Lamberton, MN. Potter discussed insect pests he has been seeing in southern Minnesota and across the state ranging from soybean gall midge, two-spotted spider mite, and corn rootworm.

Soybean gall midge continues to be a concern as a new emerging pest of soybean in southwestern counties. Larval feeding under the epidermis of plants can cause heavy yield loss through wilting and plant death, especially on field edges. Research is underway to understand this new pest's biology, but management is complicated by multiple generations throughout summer and related difficulty timing foliar insecticides. Seed treatments are not effective for controlling larvae.

Soybean gall midge larvae. Photo: Bruce Potter

Potter also detailed how to scout for and manage two-spotted spider mite in soybeans this year. Warm and dry weather we've had across much of the state is a prime environment for spider mite population growth since it can slow pathogens that normally control mite populations. High populations can especially be noticeable with webbing on the plants and a bronze appearance to the leaves. If growers decide to treat with insecticides or acaricides, options can be limited due to some organophosphate resistance and certain pyrethroids causing population flare-ups.

Corn insects such as corn rootworm continue to be an issue in parts of central and southern Minnesota. If populations of western corn rootworm are high in your fields, and you use Bt resistance traits, managing Bt-resistant populations should especially factor in to your planting and treatment planning for next year. If a field has been in continuous corn, the best option for resistance management is to rotate to a different crop next year.

This podcast was hosted by Dr. Anthony Hanson, Extension Post-Doctoral Associate. The purpose of the IPM podcast is to alert Growers, Ag Professionals and Educators about emerging pest concerns on Minnesota field crops. We also review recent pest trends and research updates.

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For IPM Program updates, visit the UMN Extension IPM website.