Discovery of Trissolcus japonicus (Hymenoptera: Scelionidae) in Ontario, Canada

We report the detection and adventive establishment of the samurai wasp, Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), a candidate classical biological control agent for the invasive Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), in southwestern Ontario, Canada. Nine naturally laid, field-collected pentatomid egg masses were collected in 2017 and 2018, and two of these egg masses, belonging to Halyomorpha halys and Podisus maculiventris (Say) (Hemiptera: Pentatomidae), produced adults of T. japonicus. The identification of T. japonicus was confirmed using DNA barcoding as well as morphological characteristics. The remaining egg masses yielded adults of the native Telenomus podisi Ashmead (Hymenoptera: Platygastridae) and Anastatus reduvii (Ashmead) (Hymenoptera: Eupelmidae).