Status and Enhancement of \u3cem\u3eTrissolcus japonicus\u3c/em\u3e (Ashmead) (Hymenoptera: Scelionidae) for Biological Control of \u3cem\u3eHalyomorpha halys\u3c/em\u3e (Stål) (Hemiptera: Pentatomidae) in Northern Utah
The invasive brown marmorated stink bug (BMSB) is a major insect pest that invades human structures causing nuisance issues and attacks numerous fruit and vegetable crops in Northern America. As this pest threatens $23 billion worth of specialty and agricultural crops in the U.S. and is difficult to manage due to insecticide resistance, control practices such as the use of biological control through egg parasitoid wasps are critical. In its native range of Asia, BMSB populations are controlled primarily by members of the Trissolcus genus such as the samurai wasp, but U.S. native wasps have demonstrated low success of BMSB egg parasitism. An introduced population of the samurai wasp was detected in Utah in 2019, and early research suggests this wasp may provide effective biological control of BMSB. This research focuses on the status and enhancement of the samurai wasp and native parasitoids in northern Utah.
Chapter II explores the range of the exotic samurai wasp and native parasitoids in northern Utah’s urban and agricultural areas and factors affecting their prosperity. The samurai wasp exhibited a strong association with BMSB, following its patterns of seasonality, orchard groundcover preference, and reliance on urban landscape resources. Samurai wasps accounted for only a small proportion of total Trissolcus parasitoid detections, and more native wasps were captured in orchards with floral groundcover as compared to those with non-floral groundcover. Chapter III assesses the attractiveness of kairomone lures to the samurai wasp in field and laboratory conditions. In the field, samurai wasp attacked lab-reared BMSB egg masses at almost an equal rate to a native Trissolcus species but had much higher emergence success from egg masses. Laboratory trials compared specific chemical blends for attractiveness to the samurai wasp. Finally, Chapter IV investigates the role of BMSB parasitoids in a state previously unsurveyed for the samurai wasp. Reported is the first record of samurai wasp in the state of Idaho and details about its population size and geographic locations. Overall, population sizes were very low, but collection of wild egg masses proved samurai wasp is taking an active role in the suppression of BMSB populations
