Orange gall midge is a newly emerging potential pest of soybeans. One of the earliest documentations of this pest was in 2011 where small, orange larvae were identified as a member of the gall midge family. At the time, it was believed they were more of a secondary pest as the adults were laying their eggs in hail-injured or fungi-decayed tissue, and any plant death or resulting yield loss was attributed to disease or plant injury, not the larvae.1
Fast forward to 2018 and a survey resulting from reports of dead or dying plants associated with the orange midge larvae was reported across 66 counties in Iowa, Nebraska, South Dakota and Minnesota.
There is still a lot to be learned from this emerging soybean pest to identify the best management practice to minimize soybean yield loss. Pest life cycle, threshold development, and insecticide timing and effectiveness are still being researched.
What Is Known?
The adult orange gall midge has black- and white-banded legs with an orange abdomen under its wings and is about ¼ inch in length.2 The white to deep orange larvae are usually found near the base of the plant in an area that is often darker and swollen (gall like) (Figure 1). Impacted plants die prematurely and depending on the stage of seed development, can result in 100% yield loss.
If you are in an area with known orange gall midge and have had injury in adjacent fields, insecticide application for emerging adults in June may be too early for effective adult control. On the later side, by the time plants are observed to be dying with larvae in the base of the stem, the damage has been done.
At this time, extension recommendations are to utilize an insecticide with residual activity after adult emergence in your area and if you experienced economical yield loss in the previous year in adjacent fields.3
What is important is to NOT assume anything when you observe dying plants in a spot on the edge of your field. Check the stem base for any orange gall midge larvae feeding and if found, contact your local university extension office.
Research continues with this new pest to help develop best management recommendations.
1 Hunt, T., Jarvi, K., and Wright, B. 2011. Gall midge larvae found in soybeans. CROPWATCH. University of Nebraska. https://cropwatch.unl.edu/.
2 McMechan, J., Hunt, T., and Wright, R. 2018. Soybean gall midge: Adult stage identified. CROPWATCH. University of Nebraska. https://cropwatch.unl.edu/.
3 McMechan, J., Hunt, T., and Wright, R. 2019. Emergence of soybean gall midge in southern Cass County, NE. CROPWATCH. University of Nebraska. https://cropwatch.unl.edu/.
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