Environment Canterbury (ECan) biosecurity officers will spend most of November inspecting more than 200 properties in Hurunui and Kaikōura to identify and remove an invasive plant – nassella tussock.
But Mid Canterbury shouldn’t think it’s out of the woods as nassella was a pest that was spreading across most of Canterbury.
It displaces other grasses leaving pasture unpalatable to stock and makes it more difficult for native species to grow.
Region-wide, there were more than 1450 properties where nassella had been found or had historically occurred. This covered more than 400,000 hectares across Canterbury.
ECan had been inspecting properties over the past few months and was now helping landowners on properties with higher-density populations. These properties contribute the vast majority of the seeds distributed annually.
Northern biosecurity team leader Matthew Smith said most land occupiers had been fantastic to work with, however, there were still some who had left their control work too late or had not booked a contractor early enough in the year.
“Most land-occupiers do an excellent job at controlling nassella and do it on time each year. By doing this they are not only protecting their assets but preventing the spread to neighbouring properties.
“Unfortunately, some continue to leave their control work until mid-November or sometimes even later, by which time seeds are becoming viable and the opportunity to prevent that happening is then lost,” he said.
To sustainably manage nassella throughout the Mid Canterbury region, land occupiers must annually search their land to identify and eliminate plants.
It’s an important job as mature plants can produce up to 100,000 seeds. Seeds can then be dispersed to neighbouring land by wind, water, stock, clothing and machinery.
“However, it’s important we recognise those who are continuing to undertake this work on time and to a high standard, as farmers are under a significant amount of pressure at the moment,” Smith said.
Originally from South America, nassella was first reported in North Canterbury in the early 1900s.
Because of its impact on the environment and farming, nassella was recognised as a serious pest by the 1940s and by the 1950s it had become so prevalent in parts of Canterbury that farmers were forced off their land.
Today, nassella is reasonably widespread throughout New Zealand’s east coasts. The Marlborough and Canterbury regions are worst affected.

• By Pat Deavoll