By Robert Koch (Professor and Extension Entomologist) and Arthur Ribeiro (Researcher)
We recently secured funding from the Minnesota Department of Agriculture to evaluate the potential threat of soybean gall midge (Resseliella maxima) to production of dry beans and other pulse crops. For part of this project, we’d like to determine the geographic extent and severity of infestations in fields of dry bean and other pulse crops in Minnesota. Therefore, this summer, if growers or their advisors/consultants suspect infestation of soybean gall midge in their fields, please contact us. Then, we'll send staff to thoroughly scout the field to determine if the suspect infestation is truly soybean gall midge and to quantify the severity of the infestation.
Image: Soybean gall midge infestation in a soybean stem.
Soybean gall midge is a challenging new agricultural pest reported from seven Midwest states. In soybean, larvae of the soybean gall midge feed inside the stems at the base of plants causing wilting, lodging and death of plants, and have resulted in significant yield reductions. This pest has been observed attacking sweet clover, alfalfa, and lead plant.
In addition, our team recently documented soybean gall midge attacking navy bean fields in Minnesota, and various other dry bean and lima bean cultivars in a preliminary field experiment. The observed symptoms of soybean gall midge infestation in dry bean were similar to those in soybean (i.e., brittle stems and dark discoloration of the stem surface around larval infestation), but also occurred at the juncture of petioles of lower leaves and the stem, and into the pith in some plants.
General guide for the identification of soybean gall midge in dry beans:
If you suspect an infestation of soybean gall midge, please contact Arthur Ribeiro (phone: 612 208 9126; email: vieir054@umn.edu) and provide a picture of the insect or injury, if possible, so further assistance can be provided.
We recently secured funding from the Minnesota Department of Agriculture to evaluate the potential threat of soybean gall midge (Resseliella maxima) to production of dry beans and other pulse crops. For part of this project, we’d like to determine the geographic extent and severity of infestations in fields of dry bean and other pulse crops in Minnesota. Therefore, this summer, if growers or their advisors/consultants suspect infestation of soybean gall midge in their fields, please contact us. Then, we'll send staff to thoroughly scout the field to determine if the suspect infestation is truly soybean gall midge and to quantify the severity of the infestation.
Soybean gall midge is a challenging new agricultural pest reported from seven Midwest states. In soybean, larvae of the soybean gall midge feed inside the stems at the base of plants causing wilting, lodging and death of plants, and have resulted in significant yield reductions. This pest has been observed attacking sweet clover, alfalfa, and lead plant.
In addition, our team recently documented soybean gall midge attacking navy bean fields in Minnesota, and various other dry bean and lima bean cultivars in a preliminary field experiment. The observed symptoms of soybean gall midge infestation in dry bean were similar to those in soybean (i.e., brittle stems and dark discoloration of the stem surface around larval infestation), but also occurred at the juncture of petioles of lower leaves and the stem, and into the pith in some plants.
General guide for the identification of soybean gall midge in dry beans:
- Infestations by soybean gall midge are most likely to happen on field edges near fields that had soybean the previous year
- Symptoms of infestation by soybean gall midge are usually seen as a dark discoloration at the base of the plant stem, but also at the juncture of petioles of lower leaves and the stem, and into the pith in some plants
- Infested stems can lodge or break easily at these areas
- Injury can result in stunting, wilting and death of plants
- Injury to plants occurs by feeding of the larval stage of soybean gall midge under the epidermis of the stem
- Peel back the epidermis of the stem and look for larvae
- Larvae of soybean gall midge are small legless maggots, clear to white-colored when young and becoming bright orange as they mature
- If such larvae are associated with white mold (Sclerotinia-infected plants) in the field, it is likely not the soybean gall midge. There is a very similar looking insect called the white-mold gall midge (Karshomyia caulicola) that feeds on the white mold fungus on various crops, and is not a crop pest. In an earlier article, we described how to distinguish soybean gall midge from white-mold gall midge.
If you suspect an infestation of soybean gall midge, please contact Arthur Ribeiro (phone: 612 208 9126; email: vieir054@umn.edu) and provide a picture of the insect or injury, if possible, so further assistance can be provided.
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