The Brown Marmorated Stink Bug, Halyomorpha halys (Stål), is a significant agricultural and urban nuisance pest. Management efforts have emphasized biological control of H. halys by parasitoid wasps in families Scelionidae and Eupelmidae. An effective technique for monitoring native and exotic parasitoids [e.g. Trissolcus japonicus (Ashmead)] is yellow sticky cards. Although yellow cards attract target wasps, they also attract numerous non-target arthropods that reduce screening efficiency. Here, we compared blue to yellow sticky cards (20.3 x 14 cm) in their attraction to target (Anastatus spp., Telenomus spp., and Trissolcus spp.) and non-target arthropods. Cards were deployed in urban landscapes, vegetable fields, and fruit orchards from June to October in 2019 and 2020. Yellow cards captured >70% of total target wasps on all cards (2,173 and 976 target wasps in 2019 and 2020, respectively). However, blue cards attracted < 30% of all non-target arthropods (76,338 and 41,991 in 2019 and 2020, respectively), primarily from orders Diptera, Thysanoptera, and Hymenoptera. In both years, target wasps were most abundant in urban sites, with Trissolcus euschisti being the most common. Trissolcus japonicus detections were low and occurred on both card colors in 2019 (yellow: n= 37, blue: n= 8) and only on yellow in 2020 (n= 29). These data support that although blue sticky cards attract fewer target wasps compared to yellow sticky cards, the improved screening efficiency given reduced non-target capture and representation of a similar target wasp species complex supports their use in parasitoid wasp surveys.
.jpg "Mark Cody Holthouse photo")