Target pest: Marrubium vulgare (Lamiales: Lamiaceae), horehound
Agent introduced: Chamaesphecia mysiniformis (Lepidoptera: Sesiidae), horehound clearwing moth
Groenteman (2019); Landcare Research (2019a) - 5 releases of C. mysiniformis were made between 8 and 21 Dec 2018 in the South Island: the Mackenzie District in the south, Marlborough in the north and North Canterbury. At one release on a farm close to Lincoln (Canterbury) the aim is to create a "nursery site" for future redistribution. The clearwing moths were released as individual eggs glued to toothpicks that were stuck that onto cut stems of horehound, allowing the newly hatched larvae to crawl down onto the cut stems, eventually reaching the roots of the plant, in which they feed.
Landcare Research (2021f) - further releases planned.
Landcare Research (2019i) - establishment success unknown (as of Aug 2019).
Landcare Research (2020c) - a little more than a year after the release of C. mysiniformis, a visit to six of the eight release sites revealed very promising early signs, although it is too early to confirm establishment. At one site larvae were found in the root-crowns of some sickly plants, and at another there were a number of dead horehound plants, including some that had received a moth egg.
Landcare Research (2021f) - established and spreading slowly at sites in the Mackenzie District and North Canterbury.
Impacts on target:
Landcare Research (2021f) - impact unknown (Aug 2021).
Impacts on non-targets:
Hill (2018) - Chamaesphecia mysiniformis has only been reported on horehound in its native Europe. The considerable phylogenetic distance between horehound and New Zealand's indigenous flora suggests that this moth is unlikely to pose a threat to native species. Host range testing was carried out in Australia in 1992/93 prior to the release of C. mysiniformis in that country and it was considered that no additional testing was required to assess the risk to non-target plant species in New Zealand. Australian results indicated that the moth is restricted to particular species within the tribe Marrubieae, and horehound is the preferred host (and, functionally, may indeed be the only host, as observed in its native range). There are no native species or other species of value growing in New Zealand that belong to the tribe Marrubieae.
EPA (2018a) - 15 May 2018 application by Horehound Biocontrol Group to import for release and/or release two moth species, Wheeleria spilodactylus and Chamaesphecia mysiniformis as biocontrol agents for the plant horehound, Marrubium vulgare. EPA Application # APP203542, approved without controls 12 Sep 2018.
EPA (2018a). EPA application APP203542: to introduce two moths (Wheeleria spilodactylus and Chamaesphecia mysiniformis) for the biocontrol of horehound (Marrubium vulgare). Environmental Protection Authority website https://www.epa.govt.nz/database-search/hsno-application-register/view/APP203542
Groenteman R (2019). Horehound biocontrol update. Landcare Research, Horehound Biocontrol Update No. 12
Hill R. (2018). EPA application [APP203542] to obtain approval to release new organisms [Wheeleria spilodactylus and Chamaesphecia mysiniformis]. Environmental Protection Authority website https://www.epa.govt.nz/assets/FileAPI/hsno-ar/APP203542/2473fc09eb/APP203542-Application.pdf
Landcare Research (2019a). Horehound agents ready for action. Weed Biocontrol: What's New? 87, February 2019. https://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/issue-87/horehound-agents-ready-for-action
Landcare Research (2019i). Who's who in biological control of weeds? Weed Biocontrol: What's New? 89, August 2019 https://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/weed-biocontrol-issue-89/whos-who-in-biological-control-of-weeds
Landcare Research (2020c). Moths away on horehound! Weed Biocontrol: What's New? 92, May 2020. https://www.landcareresearch.co.nz/news/moths-away-on-horehound/
Landcare Research (2021f). Who's who in biological control of weeds? Weed Biocontrol: What's New? 97, August 2021 https://www.landcareresearch.co.nz/publications/weed-biocontrol/weed-biocontrol-articles/whos-who-in-biological-control-of-weeds