The samurai wasp, Trissolcus japonicus, is a parasitic wasp native to Asia. It is known for attacking the brown marmorated stink bug (BMSB), an invasive pest that feeds on a variety of field, vegetable, and fruit crops.
The arrival of this wasp in the United States in 2014 garnered research attention because of its potential to suppress BMSB populations, but also because T. japonicus has been documented to attack several native stink bug species.
In 2022 and 2023 surveys detected T. japonicus individuals in St. Paul, MN. This led to a Minnesota Invasive Terrestrial Plants and Pests Center (MITPPC) funded project lead by Dr. George Heimpel and Sabrina Celis with the University of Minnesota (UMN) looking at the benefits and risks of T. japonicus in the state, beginning with surveys for the wasp, BMSB, and native stink bugs in Minnesota apple orchards. The MDA is collaborating on this project through monitoring and collecting BMSB and suspect samurai wasps throughout the state.
In 2024, two T. japonicus individual were found greater than 30 miles from the initial detection site. This indicates that while populations are currently low, T. japonicus is likely present in more of the state than is currently recognized.
Low parasitism of BMSB by native parasitoids indicated that there is an opportunity for a more effective parasitoid like T. japonicus to exert stronger control on BMSB populations. Eight species of native stink bugs were also detected in our surveys. The results of these surveys and additional lab studies will be used to determine if the benefits of having this wasp attack BMSB outweigh the potential risk to native species.
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What can you do about EAB?
- Don't import materials to Minnesota that could harbor EAB such as firewood and all ash material.
- Don't move firewood unless it's MDA Certified firewood (look for the MDA Certified Seal)
- Remember that it is illegal to move all non-coniferous firewood outside of EAB quarantine areas and into Minnesota. See map of emerald ash borer status in Minnesota.
- Become knowledgeable about recognizing EAB and remain vigilant to the condition of your ash trees.
- Stay informed on EAB by signing up to our monthly Plant Pest Insider e-newsletter.
- Don't import materials to Minnesota that could harbor EAB such as firewood and all ash material.
- Don't move firewood unless it's MDA Certified firewood (look for the MDA Certified Seal)
- Remember that it is illegal to move all non-coniferous firewood outside of EAB quarantine areas and into Minnesota. See map of emerald ash borer status in Minnesota.
- Become knowledgeable about recognizing EAB and remain vigilant to the condition of your ash trees.
- Stay informed on EAB by signing up to our monthly Plant Pest Insider e-newsletter.
- Don't import materials to Minnesota that could harbor EAB such as firewood and all ash material.
- Don't move firewood unless it's MDA Certified firewood (look for the MDA Certified Seal)
- Remember that it is illegal to move all non-coniferous firewood outside of EAB quarantine areas and into Minnesota. See map of emerald ash borer status in Minnesota.
- Become knowledgeable about recognizing EAB and remain vigilant to the condition of your ash trees.
- Stay informed on EAB by signing up to our monthly Plant Pest Insider e-newsletter.
