Enhancement of Samurai Wasp [Trissolcus japonicus (Ashmead)] for Biocontrol of Invasive Brown Marmorated Stink Bug [Halyomorpha halys (Stål)] in Utah

View the project final report

Commodities

• Agronomic: buckwheat, clovers, grass (turfgrass, sod), medics/alfalfa
• Fruits: apples, apricots, cherries, peaches
• Additional Plants: native plants, ornamentals, trees

Practices

• Crop Production: cover crops, intercropping, no-till
• Education and Training: extension, mentoring, on-farm/ranch research, workshop
• Natural Resources/Environment: biodiversity, habitat enhancement, strip cropping
• Pest Management: biological control, chemical control, competition, cultural control, field monitoring/scouting, integrated pest management, traps, weather monitoring
• Sustainable Communities: local and regional food systems, sustainability measures

The brown marmorated stink bug (BMSB, Halyomorpha halys Stål) is an invasive insect that feeds on specialty fruit and vegetable crops in North America. Current management of H. halys relies heavily on broad-spectrum insecticides which are only moderately effective and disrupt sustainable integrated pest management (IPM) programs by killing natural enemies and contributing to insecticide resistance and secondary pest outbreaks. The samurai wasp [Trissolcus japonicus (Ashmead)], a highly effective biocontrol agent native to the home range of H. halys, has shown strong promise in providing long-term and effective management of H. halys. While adventive populations of T. japonicus have been discovered in Utah, geographic distribution and climate models suggest this region is only marginally suitable. Utah’s high-elevation climate provides unique challenges to wasp establishment; therefore, conservation efforts are critical next steps to enhance T. japonicus populations. The objectives of this research were to answer: 1) What is the distribution of T. japonicus in northern Utah specialty crops and nearby urban areas, and how does the diversity of understory vegetation influence their abundance? 2) Which cover crops can increase wasp lifespan and fecundity? 3) How effective are stink bug host chemical cues (kairomones) in attracting the T. japonicus and increasing stink bug egg parasitism rates? Results were disseminated to specialty crop producers and other stakeholders through multiple presentations (webinars, grower meetings, and field days), one extension fact sheet, two newsletter articles, and two research journal publications (and one more in preparation). This research produced applicable information that supports improved sustainability of H. halys management and reduced economic losses to specialty crops.

My research focused on the status, conservation, and enhancement of an effective egg parasitoid, the samurai wasp, [Trissolcus japonicus (Ashmead)] of the invasive insect pest, brown marmorated stink bug (BMSB) (Halyomorpha halys Stål) in northern Utah by pursuing the following objectives:

• Objective 1- Determine the establishment and spread of the T. japonicus (e.g., overwinter survival) since its first detection in northern Utah in June, 2019, including assessment of the impacts of understory vegetation diversity on its occurrence and abundance.
• Objective 2- Determine cover crop floral resource candidates to attract and sustain the T. japonicus, including impacts on wasp lifespan and reproduction.
• Objective 3- Determine the viability of stink bug host chemical cues (kairomones) in attracting T. japonicus and increasing egg parasitism rates in both a field and mesocosm setting.

After reviewing preliminary results from Objective 2, research efforts were shifted towards a second experiment as a part of Objective 3 (mesocosm arena assessment of T. japonicus response to kairomones).

My educational objectives focused on increasing the knowledge of specialty crop producers, research and extension colleagues, the general public, youth, and other interested stakeholders on conservation and enhancement of the T. japonicus for biological control of the invasive brown marmorated stink bug (BMSB; Halyomorpha halys).

• Objective 1- Promote the T. japonicus for the sustainable management of BMSB to approximately 10,000 specialty crop producers and other relevant stakeholders.
• Objective 2- Add to the national H. halys research knowledge base and share project results with professional colleagues through two journal publications and three scientific conference presentations.
• Objective 3- Disseminate information on invasive species and sustainable pest management to the general public via varied outreach venues and formats.