Biocontrol introduction

Target pest: Hieracium spp. (Asterales: Asteraceae), hawkweed

Agent introduced: Macrolabis pilosellae (Diptera: Cecidomyiidae), hieracium gall midge

Imported:

Late-1990s, 1999, 2001

Import source:

Switzerland

Import notes:

Smith (2007b) - several shipments were imported by Landcare Research, in conjunction with the Hieracium Control Trust, in the late 1990s for testing.

Released:

2002

Release details: Smith (2007b) - first field release 2002 and widely released in subsequent years.

Establishment:

Smith (2007b) - established at many sites in both islands but not widespread.

Landcare Research - (2014c) - common near Waiouru.

Landcare Research (2020e) - surveys in 2020 at release sites - Canterbury and Otago in the South Island (Marlborough release sites were not visited) and on the Central Plateau of the North Island - showed M. pilosellae has established in both the North and the South Islands. In the South Island M. pilosellae was recovered from 73% of the sites and were only present near the original release sites; in the North Island it was recovered from 80% of release sites, dispersing over 10 square kilometres from the original release sites.

Impacts on target:

Hayes et al. (2013) - data from a study area on the Central Plateau of the North Island suggest M. pilosellae is reducing mouse-ear hawkweed (Pilosella officinarum, syn. Hieracium pilosella) cover by 26% after 10 years and that other vegetation is replacing it.

Landcare Research (2014c) - at Waiouru has reduced host cover by 18% over 6 years; also very damaging in laboratory trials.

Landcare Research (2020e) - 2020 surveys showed 9.5% of hieracium plants at South Island sites where the midge was present were galled by the midge. In a 2006 study up to 33% had been galled by M. pilosellae. The 2006 study also showed that the gall midges had reduced hieracium cover by up to 18% at sites in the North Island, where galling was most intense. It is now known that biocontrol of hieracium is not very effective in the South Island. Although site comparisons over time show that hieracium densities have been reduced by 10% in the South Island, this is predominantly attributed to changes in land management practices, such as irrigation, cultivation and reduced grazing pressure, rather than biocontrol.

Impacts on non-targets:

Hieracium Control Trust (2000) - host range tests were completed on 66 test plant species comprising 9 species from the genus Hieracium, 29 species in the family Asteraceae, including the closest relatives to Hieracium among native New Zealand plants, and 28 species from an additional 25 families of plants. Oviposition and larval development tests were carried out in Switzerland, or under insect containment conditions in New Zealand for those plants that could not be grown in Switzerland. No eggs were laid on plants other than Hieracium species, and no larvae survived on any plants other than Hieracium species. There are no native plants in the genus Hieracium; the genus is represented in New Zealand by weedy species introduced from Europe. The host range tests indicate the likelihood that any non-target species will be negatively affected is very low.

Paynter et al. (2015) - surveys of potential non-target hosts the hawkweeds Hieracium aurantiacum and H. praealtum, both exotic weeds, (H. pilosella is listed as the target weed) showed no feeding on former and minor 'spillover' feeding on latter.

EPA Applications:

EPA (1998a) - 26 Aug 1998: application by the Hieracium Control Trust to import into containment a new organism Macrolabis pilosellae (Binne, 1878), for the purpose of testing to determine its suitability as a biological control agent against hieracium. EPA Application # NOC98001, approved with controls 9 Oct 1998.

EPA (2001) - 17 Nov 2000: application by the Hieracium Control Trust to import for release the insects Macrolabis pilosellae (Binnie 1878), Cheilosia urbana (Meigen 1822) and Cheilosia psilophthalma (Becker 1894) for the purpose of biological control of hawkweeds, Hieracium spp. EPA Application #NOR00001, approved without controls 27 Jun 2001.

References

Auckland Regional Council (). The Land 99 http://greensite.arc.govt.nz/library/:70039-2.pdf

EPA (1998a). EPA application NOC98001: to import into containment a new organism Macrolabis pilosellae (Binne, 1878), for the purpose of testing to determine its suitability as a biological control agent against hieracium. Environmental Protection Authority website https://www.epa.govt.nz/database-search/hsno-application-register/view/NOC98001

EPA (2001). EPA application NOR00001: to import for release the insects Macrolabis pilosellae (Binnie 1878), Cheilosia urbana Meigen and Cheilosia psilophthalma (Becker 1894) for the purpose of biological control of hawkweeds, Hieracium spp. Environmental Protection Authority website https://www.epa.govt.nz/database-search/hsno-application-register/view/NOR00001

Hayes L, Fowler SV, Paynter Q, Groenteman R, Peterson P, Dodd S, Bellgard S (2013). Biocontrol of weeds: achievements to date and future outlook. In: Dymond JR (ed) Ecosystem services in New Zealand: conditions and trends. Manaaki Whenua Press, Lincoln, pp 375-385 https://www.landcareresearch.co.nz/__data/assets/pdf_file/0005/77054/2_8_Hayes.pdf

Hieracium Control Trust (2000). Application to EPA (NOR00001) to import for release the insects Macrolabis pilosellae (Binnie 1878), Cheilosia urbana Meigen and Cheilosia psilophthalma (Becker 1894) for the purpose of biological control of hawkweeds, Hieracium spp. Environmental Protection Authority website https://www.epa.govt.nz/assets/FileAPI/hsno-ar/NOR00001/6b046d0b38/Application-NOR00001.pdf

Landcare Research (2014c). Who's who in biocontrol of weeds? What's new in biological control of weeds? 69: 10-11 https://www.landcareresearch.co.nz/assets/Publications/Weed-biocontrol/WhatsNew69.pdf

Landcare Research (2020e). Hieracium biocontrol â€“ 20 years on. Weed Biocontrol: What's New? 93, Aug 2020 https://www.landcareresearch.co.nz/publications/weed-biocontrol/weed-biocontrol-articles/hieracium-biocontrol-20-years-on/

Paynter QE, Fowler SV, Gourlay AH, Peterson PG, Smith LA and Winks CJ (2015). Relative performance on test and target plants in laboratory tests predicts the risk of non-target attack in the field for arthropod weed biocontrol agents. Biological Control 80: 133-142 https://doi.org/10.1016/j.biocontrol.2014.10.007

Smith L (2007b). Hieracium Gall Midge. In The Biological Control of weeds Book (Landcare Research) http://www.landcareresearch.co.nz/research/biocons/weeds/book/documents/Hieracium_Gall_Midge.pdf