Evaluating methods to detect and monitor North American larval parasitoids of the emerald ash borer (Coleoptera: Buprestidae)

Populations of native North American parasitoids attacking Agrilus Curtis (Coleoptera: Buprestidae) species have recently been considered as part of an augmentative biological control programme in an attempt to manage emerald ash borer, Agrilus planipennis Fairmaire, a destructive wood-boring beetle discovered in North America in 2002. We evaluate trapping methods to detect and monitor populations of two important native larval parasitoids, Phasgonophora sulcata Westwood (Hymenoptera: Chalcididae) and Atanycolus Forster (Hymenoptera: Braconidae) species, attacking emerald ash borer in its introduced range. We found that purple prism traps captured more P. sulcata than green prism traps, yellow pan traps, and log samples and thus were considered better for detecting and monitoring P. sulcata populations. Trap type did not affect the number of captures of Atanycolus species. Surprisingly, baiting prism traps with a green leaf volatile or manuka oil did not significantly increase captures of P. sulcata or Atanycolus species. Based on these results, unbaited purple prism traps would be optimal for sampling these native emerald ash borer parasitoids in long-term management programmes.