Environmental officials took over the usually relaxed farmers market in Kerikeri on Saturday with a warning for locals.
Ministry of Primary Industries field operations manager Mark Bateman says they're hoping to keep plant growers vigilant for the signs of Myrtle Rust.
"At the start of the market we had scientists who were examining plants when they came in to make sure people were aware of what we're looking for and their plants were risk free."
Growers are urged to report any signs of the yellow fungus that can kill pohutukawa, rata, mānuka and other plants in the Myrtle family.
It normally attacks soft, new leaf growth.
Nursery owner Judy Rijavez says it's not only our plants, but our reputation that's at stake.
"New Zealand has a really good name in export, in exporting mānuka honey, [and] in exporting timber."
At the moment the disease is being contained after being found in a nursery on Tuesday.
Another nursery stopped selling myrtles like feijoas immediately and has since been given a clean bill of health.
But Kerikeri nursery manager Sandy Johnson says the arrival of the fungus is devastating.
"Especially in this area where we're big feijoa growers; along with the guava fruit moth we've also got this problem as well. Pohutukawas become affected and that's a huge part of our business and our national identity."
Mr Bateman fears it could do even more damage.
"If it does become more virulent and widespread then the risk is quite severe for New Zealand, it's a serious critical issue for us."
MPI says Myrtle Rust can arrive in any part of the country so it's important members of the public remain vigilant.
Newshub.
