Samurai wasp (Trissolcus japonicus)
Biocontrol Agent Factsheet
The samurai wasp is one of the most effective natural enemies of the brown marmorated stink bug.
Overview
Pests Targeted: Brown marmorated stink bug
Pest Stage: Eggs
Commercially Available? No
Scientific Name: Trissolcus japonicus
Biocontrol Agent Type: Parasitoid (lays eggs in brown marmorated stink bug eggs).

Common Names
Samurai wasp (may be changing)
Relative effectiveness
The samurai wasp is one of the most effective natural enemies of the brown marmorated stink bug. In their native range, a samurai wasp can kill up to 80% of stink bug eggs, usually attacking all eggs in an egg mass (or group) (Yang et al. 2009). Research on its impact in North America is ongoing.
Where to use
This tiny wasp should be conserved rather than released, and is being found in more places where brown marmorated stink bugs are present. It can be found in rural and urban areas, in gardens and on farms, as well as in the landscape.
About samurai wasp
The samurai wasp (Trissolcus japonicus) is a tiny wasp that is a natural enemy of the brown marmorated stink bug. It is a parasitoid of stink bug eggs, meaning that it kills stink bugs by laying its own eggs inside of stink bug eggs. The developing parasitoid kills the stink bug before it hatches. After approximately 10-14 days, the adult wasp emerges from the eggs. Females wasps seek out additional stink bug eggs to attack.
- Native/Non-native: Non-Native
- Preferred climate: temperate
- Region: Currently found throughout much of the northeastern and west coast USA, but its range has been expanding.
- Established: Yes
Samurai wasp appearance
Adult samurai wasps are black, shiny, and very small (1.0-2.0 mm or 0.4-0.8 in) with black and yellow-brown legs and antennae. They have two pairs of transparent wings.

Adult female samurai wasp. Egg and larval stages occur within stink bug eggs and are therefore not observed without dissection of the eggs.

Brown marmorated stink bug eggs parasitized by a samurai wasp. Note the darkened color indicating the presence of developing wasps.

Adult samurai wasp emerging from a brown marmorated stink bug egg.
How to use samurai wasp for biocontrol
Biocontrol category:
- Classical - released once and persists
- Conservation - attract and protect from the surrounding environment
Maximizing effectiveness: Avoid broad-spectrum insecticide sprays and always apply chemical controls in accordance with the label, as samurai wasps are very susceptible to insecticides (Lowenstein et al. 2019). Nearby wooded, weedy, and other relatively undisturbed habitats may provide nectar required by samurai wasps to survive and reproduce (McIntosh et al. 2020), as well as overwintering habitat.
Pest stage: Eggs
Mode of action: Parasitoid (lays eggs in brown marmorated stink bug eggs).
Compatibility: The samurai wasp is generally incompatible with insecticides (see Maximizing effectiveness). (Any time you use a pesticide, you must read and follow the label directions and comply with all applicable laws and regulations related to pesticide use. Also be sure that any pesticide used is approved for use in your country and state/province.)
Commercially available: No
About Brown marmorated stink bug (Halyomorpha halys)
Brown marmorated stink bug (BMSB) feeds on more than 170 known plants including row crops, tree fruit, and vegetables. Both adults and nymphs cause visible injury to host plant fruit when they insert their stylets, or mouthparts, to feed. Injury symptoms vary depending upon the crop type. For example, feeding injury on apples and peaches causes depressions on the skin of the fruit and dark, corky spots throughout the flesh, whereas on soft vegetables such as tomatoes, the damage is white and spongy on the surface and throughout. For a more comprehensive list of crops and damage symptoms, see Rice et al. 2014.

Adult brown marmorated stink bug feeding on apple. Both adults and nymphs reduce fruit quality through feeding.

Brown marmorated stink bug eggs laid on underside of Peperomia spp. Leaf.

Brown marmorated stink bug nymphs on a nectarine, alongside depressions indicative of damage caused by stink bug feeding.
Authors
Dr. Nicole F. Quinn
USDA-ARS Beneficial Insects Introduction Research Unit and University of Massachusetts
Dr. Laura J. Nixon
USDA-ARS Appalachian Fruit Research Station and ORISE
Date: November 2021
- Lowenstein, D. M., H. Andrews, A. Mugica, N. G. Wiman, and A. Nielsen. 2019. Sensitivity of the egg parasitoid Trissolcus japonicus (Hymenoptera: Scelionidae) to field and laboratory-applied insecticide residue. Journal of Economic Entomology 112: 2077-2084.
- McIntosh, H. R., V. P. Skillman, G. Galindo, and J. C. Lee. 2020. Floral resources for Trissolcus japonicus, a parasitoid of Halyomorpha halys. Insects 11: 413.
- Rice, K. B., C. J. Bergh, E. J. Bergmann, D. J. Biddinger, C. Dieckhoff, G. Dively, H. Fraser, T. Gariepy, G. Hamilton, T. Haye, A. Herbert, K. Hoelmer, C. R. Hooks, A. Jones, G. Krawczyk, T. Kuhar, H. Martinson, W. Mitchell, A. L. Nielsen, D. G. Pfeiffer, M. J. Raupp, C. Rodriguez-Saona, P. Shearer, P. Shrewsbury, P. D. Venugopal, J. Whalen, N. G. Wiman, T. C. Leskey, and J. F. Tooker. 2014. Biology, ecology, and management of brown marmorated stink bug (Hemiptera: Pentatomidae). Journal of Integrated Pest Management 5: 1-13.
- Yang, Z. Z.-Q., Y. Y.-X. Yao, L.-F. L. Qiu, and Z. Z.-X. Li. 2009. A new species of Trissolcus (Hymenoptera: Scelionidae) parasitizing eggs of Halyomorpha halys (Heteroptera: Pentatomidae) in China with comments on its biology. Annals of the Entomological Society of America 102: 39-47.
- Adult samurai wasp emerging from a brown marmorated stink bug egg. Photo credit: E.J. Talamas
- Adult female samurai wasp. Egg and larval stages occur within stink bug eggs and are therefore not observed without dissection of the eggs. Photo credit: E.J. Talamas
- Brown marmorated stink bug eggs parasitized by a samurai wasp. Note the darkened color indicating the presence of developing wasps. Photo credit: N.F. Quinn
- Adult samurai wasp emerging from a brown marmorated stink bug egg. Photo credit: E.J. Talamas
- Adult brown marmorated stink bug feeding on apple. Both adults and nymphs reduce fruit quality through feeding. Photo credit: N.F. Quinn
- Brown marmorated stink bug eggs laid on underside of Peperomia spp. Leaf. Photo credit: L.J. Nixon.
- Brown marmorated stink bug nymphs on a nectarine, alongside depressions indicative of damage caused by stink bug feeding. Photo credit: J. Hepler.
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