Trissolcus japonicus Ashmead (Hymenoptera: Scelionidae) is an endoparasitoid of the eggs of the brown marmorated stink bug, Halyomorpha halys Stål (Hemiptera: Pentatomidae), a major agricultural pest native to China, Japan, South Korea and Taiwan. We used CLIMEX to estimate the potential global distribution of T. japonicus with particular reference to New Zealand. In its native range the model predicts the presence, or a potential expansion, of T. japonicus into most of humid-subtropical and humid-continental areas. Globally, the model projects that many temperate, Mediterranean and subtropical areas could suit the establishment of T. japonicus. In New Zealand, the north appears moderately to highly suitable for T. japonicus, while southern regions are mostly marginal. The risk posed by T. japonicus to non-target species in New Zealand is predicted to vary between different non-targets. CLIMEX projections of the potential distribution of T. japonicus provide guidance for release sites of this parasitoid if approved for importation and release in New Zealand.

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is native to northeast Asia. It was accidentally introduced to Europe and North America, where it has become a key pest, feeding on many important crops. Previous eco-climatic niche modelling indicates that H. halys could expand its distribution vastly, and numerous border interceptions of this pest in many countries, including Australia and New Zealand, indicate that it would be prudent to prepare for its eventual arrival. Similar niche modelling was used to assess the potential distribution of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), the key parasitoid of H. halys in China. Trissolcus mitsukurii (Ashmead) is one of the main parasitoids of H. halys in Japan. It is known to have existed in Australia since the early 20th century and was also specifically introduced to Australia in the 1960s, and it has now also invaded Italy. We used CLIMEX to model the climatic niche of T. mitsukurii to estimate its global potential distribution. We found that T. mitsukurii should be able to significantly expand its range globally, and that there is a significant degree of overlap in the projected ranges of T. mitsukurii, T. japonicus and H. halys. From a biological control perspective, this implies that the two Trissolcus species may be able to help mitigate the potential impacts of H. halys.

In July 2010, the Environmental Risk Management Authority New Zealand (now the Environmental Protection Authority) gave approval for release of the parasitoid Cotesia urabae Austin and Allen (Hymenoptera: Braconidae) as a biological control agent for the gum leaf skeletoniser Uraba lugens Walker Lepidoptera: Nolidae) in New Zealand. Between January and June 2011, five releases of adult C. urabae were made at two different sites in Auckland: three at the Auckland Domain (91 female: 102 male) and two at the Manukau Memorial Gardens (86 female: 54 male). Both release sites were closely monitored throughout 2011. The first cocoons were found one month after the first release, and thus far 132 cocoons have been found at the release sites suggesting initial establishment. The first confirmed progeny of field emerged parents was confirmed at the Auckland Domain in February 2012 with the finding of 18 cocoons at that site. Monitoring is continuing to determine if the population persists and further releases are planned at other sites to ensure establishment. Results of this study along with data gathered from ongoing monitoring will be useful to provide advice and guidelines to replicate a similar biocontrol program in other countries affected by U. lugens in the future.