Chilean needle grass. Photo: Supplied / Marlborough District Council
The Environmental Protection Authority has approved the release of a rust fungus to control the spread of the highly invasive Chilean needle grass in Marlborough.
It was first recorded in the 1940s in the Blind River area and has spread to 2615 hectares across the district.
Council biosecurity manager Liam Falconer said it's hoped the fungus will become well established in Marlborough, slowing the growth and seeding ability of the needle grass.
It forms dense clumps, excludes pasture species and reduces farm productivity - which has the potential to cost farmers millions of dollars in lost production. The seeds also have sharp tips that can get into pelts and eyelids, causing blindness in animals.
Marlborough District Council biosecurity manager Liam Falconer with an example of Chilean needle grass at the Wither Hills Farm Park near Blenheim. Photo: Supplied / Marlborough District Council
Marlborough District Council applied to use a strain of rust fungus (Uromyces pencancus) as a biocontrol agent against Chilean needle grass (Nassella neesiana) in 2017.
"This rust fungus is host‐specific, meaning it only lives on Chilean needle grass and is highly unlikely to harm native plants or animals."
Falconer said the fungus did not pose any risk to humans.
"Testing shows this rust fungus can successfully slow infestations, killing the foliage of Chilean needle grass as well as reducing its growth and seed production."
Falconer said biocontrol was a long game and it could take a number of years before an impact from the initial releases was seen.
Councillor Barbara Faulls, who holds council's biosecurity portfolio, said without an intervention such as the fungus, farmers, landowners and biosecurity staff were fighting an uphill battle against the damaging weed.
"Rust fungus will hopefully give us the advantage of not having to search for the proverbial 'needle in a haystack', as it will spread and do its job without too much human intervention."
A study has estimated the potential cost of lost production could reach as much as $1.16 billion nationally, if the weed is left unchecked.
