6: Trissolcus japonicus host orientation to Halyomorpha halys: Determining potential long-distance chemical cues

Parasitoids utilize several cues to navigate complex landscapes to find their hosts. These cues can include adult associated kairomones, aggregation pheromones, and host induced plant volatiles from herbivory and oviposition. Recently, adventive populations of the samurai wasp, Trissolcus japonicus (Ashmead) have been discovered in the United States. This species is a co-evolved host of the brown marmorated stink bug, Halyomorpha halys (Stål), an invasive species from Asia which is a severe agricultural pest in the Mid-Atlantic region of the U.S. It is important to determine where and when T. japonicus can be found to understand it’s potential as a biological control agent for H. halys. This study sought to identify if chemical cues associated with H. halys adults are attractive to T. japonicus and may be useful in searching for T. japonicus populations. A laboratory behavioral assay and field trial using yellow sticky cards was conducted to determine if T. japonicus females are attracted to commercial H. halys lures. A greenhouse trial was conducted to determine if H. halys feeding and oviposition induced a change in volatile emissions in potted Prunus persica (L.), cultivated peach, and Ailanthus altissima (Mill.), tree of heaven. Our results indicate that while T. japonicus may not be attracted to the components in the commercial H. halys lure, H. halys feeding and oviposition does induce changes in volatile emissions in both plant species. It may be possible that T. japonicus uses host plant associated cues to orient to H. halys eggs in the wild.