Research HighlightsSearching for Soybean Tentiform Leafminer Control Methods
In this article, you’ll find details on:
- A new-to-soybean pest, the soybean tentiform leafminer is now in four states
- Minnesota entomologists are evaluating control methods for the insect
- Translaminar insecticides show promise
- Several parasitic wasps, natural enemies of the leafminer, could provide extra control
By Carol Brown
A native North American moth commonly found in forested areas, the soybean tentiform leafminer has expanded its diet. The insect was first sighted in Canadian soybean fields in 2016. Robert Koch, University of Minnesota Extension Entomologist, identified the soybean tentiform leafminer in Minnesota in 2021. And now it has also been found in North Dakota, South Dakota and Nebraska soybeans.
“The soybean tentiform leafminer is a tiny moth whose larvae, or caterpillars, live inside and feed on soybean leaves,” explains Koch. “Through their feeding, the caterpillars are hollowing out, or mining, the leaf tissue and then those tissues die, reducing the plant’s ability for photosynthesis. A single caterpillar doesn’t destroy a large area within a plant, but over a season, the damage will add up from numerous caterpillars and multiple generations of the moth.”
He is leading the research on this pest through funding from the Minnesota Soybean Research and Promotion Council, the Minnesota Rapid Agricultural Response Fund with the University of Minnesota, and as part of a larger project with the North Central Soybean Research Program. Koch and his team started at the basics, learning about the soybean tentiform leafminer’s lifecycle, emergence times, and the levels of damage the larvae can inflict. They continue to track the moth’s geographic expansion with annual surveys. The 2025 survey will be distributed in June.
Currently, Koch and his team are exploring how to reduce its impact on soybeans with insecticides and through biological control.
“The translaminar type of insecticides are showing promise,” he says. “These insecticides have properties that penetrate the leaf to reach the larvae as opposed to other types that remain on the leaf surface. Through lab and greenhouse studies, we found this type of insecticide can be effective. With in-field tests, although there weren’t high infestation levels, the translaminar insecticides provided some protection of the soybean leaves.”
Going up the Food Chain
The team is also exploring natural control of the pest and found there are approximately 20 species of parasitic wasps that feed on the soybean tentiform leafminer.
“It is exciting to find this high number, especially when compared to other insects such as the soybean aphid, which only a few types of parasitic wasps feed upon,” Koch says. “We are trying to identify all the different parasitic wasps and the impact they can have at controlling populations.”
The team is looking in both soybean fields and the forested areas where the leafminer traditionally lives to compare wasp species in the two habitats. The goal, Koch says, is to learn more about parasitic wasp biology and find how farmers could make the soybean field a more hospitable place for these valuable wasps.
Leafminer Genome Sequenced
The soybean tentiform leafminer’s genome has been completely sequenced, which means researchers can use this genetic map to find additional control methods. They are using this information to explore its genetic variability across different geographic locations as well as comparing leafminers on soybeans versus the populations on native plants. Koch thought there would be distinct populations that are feeding on the soybeans, but isn’t seeing definite differences between them.
The team is also exploring soybean cultivars for potential resistance to the insect.
“We have already found some soybean lines that were less suitable. They chose not to lay eggs on the plant or the caterpillars didn’t survive as well,” he says. “If this pest continues to be a problem, we could work with soybean breeders to find additional lines or develop ones that have resistance to the soybean tentiform leafminer.”
Additional Resources
The Genome Sequence and Genomic Diversity of the Soybean Tentiform Leafminer – G3 journal article
Evaluation of the Toxicity of Translaminar Insecticides Against the Soybean Tentiform Leafminer (Lepidoptera: Gracillariidae), a Potential New Pest of Soybean – Journal of Economic Entomology
Immature Development and Adult Longevity of the Soybean Tentiform Leafminer – Environmental Entomology
A North American Moth is Expanding its Turf to Soybeans – SRIN article
Research and Extension on Emerging Soybean Pests in the North Central Region – National Soybean Checkoff Research Database project
Meet the researcher: Robert Koch
Published: Jul 7, 2025
The materials on SRIN were funded with checkoff dollars from United Soybean Board and the North Central Soybean Research Program. To find checkoff funded research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.
