The Environmental Protection Authority [EPA] has approved the import and release of an Australian wasp to control the spread of an invasive wattle weed, previously found in Wairarapa.
It said the decision to approve the bud-galling wasp [Trichilogaster acaciaelongifoliae] follows comprehensive EPA assessments that found it will provide a highly specific and sustainable tool to control Sydney golden wattle [Acacia longifolia].
Te Papa’s botanical specimen of the Sydney golden wattle was collected from Western Lake Rd in Featherston in 2011.
The EPA said the decision to release the wasp was based on risk assessments and studies.
“The EPA considers it highly unlikely it would displace or harm any native species.”
The wasp, which is only a few millimetres long, does not sting or bite, and there is no risk to human health.
EPA general manager of hazardous substances and new organisms Dr Chris Hill said the wasps were “quite docile” and only active for a few weeks a year.
“They prefer to remain near the host plant, further reducing any possible risk to our native plants and animals.”
The EPA said bud-galling wasps could control the spread of Sydney golden wattle by laying their eggs in flower buds, which induced abnormal growths, preventing flowers from forming and seed production.
Since being introduced in New Zealand in the late 19th century, the invasive plant has spread broadly in the North Island and significantly reduced biodiversity in two of Aotearoa’s most threatened environments – dunes and wetlands.
The EPA said the wattle had a similar negative impact on biodiversity in countries around the world.
It also forms dense thickets that increase fire hazards in areas it invades.
Hill said risk assessments found that introducing the wasp as a biocontrol agent would help reduce the reliance on chemical pesticides to combat the Sydney golden wattle.
“In the long term, and allow native plant species to return.”
“This will, in turn, reduce fire hazards, increase water availability and attract native animals.”
Horizons Regional Council in the Manawatū-Whanganui region applied to import and release the bud-galling wasp on behalf of the National Biocontrol Collective, a group of regional and district councils and the Department of Conservation (DOC).
The EPA publicly consulted on this application and received 49 submissions, with 31 submissions in support, 16 opposed, and two neutral.
