Biosecurity teams are busy searching dairy farms for the weed velvetleaf, described as Southland's equivalent of a fruit fly outbreak.
Seventy-six staff from councils in Southland are searching farms across the region, in an attempt to inspect crops before velvetleaf plants drop their seeds and spread further.
Velvetleaf is considered one of the world's worst weeds, and more than 60 plants have been found in 10 farms across Southland.
READ MORE:
If velvetleaf takes hold, it can take over paddocks, reducing crop yield by 30 to 90 percent.
More than 1400 hectares of farmland needs to be searched in the Southland region alone, a process which could take up to two months.
The noxious weed has yellow flowers and heart-shaped leaves. It's believed the outbreak was caused by contaminated fodder beet seed imported last year, and unknowingly planted by farmers here.
The Southland region grows half the country's national crop of fodder beet, used as winter feed for dairy cows.
Biosecurity officer for Environment Southland Adam Brown says at the moment, contamination levels are very low. However each plant can release up to 1000 seeds, and within a few years thousands of velvetleaf plants could be growing amongst crops.
The weed gives off chemicals which can inhabit growth of the vegetation around it, which is not good news when it's growing in crops, Mr Brown says.
It also competes with crops for nutrients, water, space and light.
Mr Brown says it might only be a couple plants per property for now, but it's important to find it all.
"Potentially it's a really bad issue," he says. "It's not just a Southland problem -- it's a nationwide problem."
The teams are sweeping entire paddocks back and forth to spot velvetleaf plants.
Mr Brown says normally it's easy to spot as it grows tall, however colder weather in Southland meant it wasn't as high and is more difficult to find.
Some mature seed pods have been found but the vast majority haven't got to that stage yet, he says.
Velvetleaf plants (Dave Goosselink)
Environment Southland is working with Asure Quality, acting for the Ministry of Primary Industries (MPI), and the Southland District Council to combat the weed.
Border security has also stepped up to try and prevent any more cases of the weed from entering the country.
Southland District Council chief executive Steve Ruru says it is important the district council is supporting the response, as it is a major issue for its rural communities.
"If the plant becomes fully established in Southland it will be extremely bad for the farming community, and what is bad for the farming community is bad for Invercargill," he says.
MPI is taking samples from consignments, which are being sent to a specialist laboratory for inspection.
Anybody who finds a suspected velvetleaf plant should leave it where it is, mark its location, photograph it and contact MPI.
Mr Bowman said it is important people do not pull the plants out and move them, as this could cause seeds to drop and the plants to spread.
Farmers are also being urged to do their bit by checking their own crops regularly and reporting any signs to MPI on 0800 80 99 66.
Newshub.
