New biocontrol agent deployed to control Chilean needle grass
The new biological control agent (Uromyces pencanus) was released near Spotswood in north Waitaha Canterbury earlier this month to help tackle the highly invasive plant, Chilean needle grass (CNG).
The Environmental Protection Agency (EPA), the agency responsible for approving new biological control agents in Aotearoa, granted approval for the release in July 2024 with the first releases made throughout October in Canterbury and Marlborough.
Chilean needle grass is a serious threat to agriculture and has the potential to cost an estimated $1.16 billion in lost production across Aotearoa, if left uncontrolled. It is unpalatable to stock, and has sharp seed heads that can penetrate pelts, contaminate wool and cause blindness in livestock.
Once established, it can be difficult and costly to control with seed spreading very easily on clothing, machinery, vehicles, feed and on livestock.
Chilean needle grass populations are very localised in Canterbury, with the majority of known sites in north Canterbury with one other site in West Melton.
Rust fungus kills pest plant
Uromyces pencanus is a rust fungus that damages the top layer of the Chilean needle grass leaves causing increased water loss and premature death. This technique is successful in dry conditions - a potential match made in heaven for north Canterbury conditions.
CNG rust mixed with talcum powder painted onto leaf
Invasive species advisor Dr Morgan Shields said that he has his fingers crossed for the success of the Chilean needle grass rust in Waitaha Canterbury.
"Biocontrol is an excellent tool but also a fickle thing. You can do all the testing but never quite know how successful it will be until sometimes years down the track," Morgan said.
"The rust is host specific, meaning that it will only attack Chilean needle grass."
It’s been a long road to get this rust into Aotearoa from its native home of South America. It was first approved for release here in 2011 but researchers from Manaaki Whenua Landcare Research had to wait a decade for the export permit from Argentina before importing it in 2022.
Find out more
- Visit the Environmental Protection Agency (EPA) website.
- If you would like to learn more about Chilean needle grass rust and other biological control agents, visit Manaaki Whenua Landcare Research.