Target pest: Marrubium vulgare (Lamiales: Lamiaceae), horehound
Agent introduced: Wheeleria spilodactylus (Lepidoptera: Pterophoridae), horehound plume moth
MPI (2018) - specimens were imported on 2 Oct 2018 as adults reared from larvae field-collected in Australia; their identity was confirmed as Wheeleria spilodactylus (Lepidoptera, Pterophoridae) by Landcare Research Lepidopterist Robert Hoare.
Groenteman (2019); Landcare Research (2019a) - 8 releases of W. spilodactylus 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 plume moths were released as larvae on cut stems and foliage of horehound, sprinkled onto horehound plants at release sites.
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 W. spilodactylus a visit to six of the eight release sites revealed barely any evidence of plume moth activity. However, there is evidence of the presence of the moth and it may be too soon to expect significant signs of activity.
Landcare Research (2021f) - established at sites in North Canterbury and Marlborough.
Impacts on target:
Landcare Research (2021f) - causing obvious damage already (Aug 2021).
Impacts on non-targets:
Hill (2018) - Wheeleria spilodactylus has only been reported on horehound and on Ballota nigra 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 W. spilodactylus 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. There are no native species or other species of value growing in New Zealand that belong to the tribe Marrubieae. The risk of colonisation of plants other than Marrubium species following release in New Zealand is considered negligible.
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
MPI (2018). Horehound plume moth identification. Ministry for Primary Industries, Wheeleria spilodactylus importation documentation.