The EPA has approved the release of a rust fungus to control the spread of Chilean needle grass. This invasive weed harms animals and can cost farmers millions of dollars in lost production.
Marlborough District Council applied to use a strain of rust fungus, Uromyces pencanus, as a biocontrol agent against Chilean needle grass (Nassella neesiana) in New Zealand.
“We hope introducing this rust fungus will help slow the spread of this aggressive weed and reduce harm to livestock and other farm animals,” said Dr Chris Hill, General Manager of Hazardous Substances and New Organisms.
“Testing shows this rust fungus can successfully slow infestations, killing the foliage of the Chilean needle grass and reducing its growth and seed production.”
This rust fungus is highly host‐specific, meaning it only lives on Chilean needle grass. Results have shown that it is doubtful it will harm native plants or animals, and there is also no risk to people.
Chilean needle grass is a South American perennial grass first identified in New Zealand in the 1920s. Its seeds have sharp tips that can bore into the eyelids and pelts of animals, resulting in severe animal welfare issues, including blindness.
Plants form dense clumps, which exclude pasture species and are less palatable to stock, reducing farm productivity.
Methods for managing Chilean needle grass infestations on farms, such as destocking for the three-month period when seeds are present or applying herbicide, can be difficult and expensive.
One study estimated that if the weed was left unchecked, the potential cost of lost production across the sector could reach as much as $1.16 billion.
Chilean needle grass has been well established in some regions, particularly Hawke’s Bay, Marlborough, Auckland and Canterbury.
“Our panel of independent experts approved this release following a rigorous, evidence-based investigative process which included the consideration of public submissions, international best practice and engagement with mana whenua.”
In recent years, the EPA has approved other biocontrol agents for weeds such as old man’s beard, Sydney golden wattle, and moth plant.
