A new project is underway to more accurately gauge the impact alligator weed has on farmland across the upper North Island.
The invasive pest plant is one of the world’s worst weeds and the three-year AgResearch project also aims to provide practical mitigation and management advice and education to farmers, growers and rural contractors.
The weed grows on land and in water, where it forms floating mats.
It can quickly grow on pasture, out-competing grass and crops, leading to reductions in production and profit.
It also can cause health problems to livestock if eaten, including blindness.
The project has received $270,000 from the Ministry for Primary Industries Sustainable Food and Fibre Futures Fund and is headed by AgResearch senior scientist Trevor James.
He hopes there was enough information collected around alligator weed’s impact on land by the end of the project’s conclusion.
“A lot of it is anecdotal and there’s a lot of stuff we don’t know and hopefully in three years’ time, we’ll know a lot more.”
The project could also provide a basis for data to calculate the weed’s economic impact on farming.
While its impact in waterways was well known, the pest plant was increasingly becoming invasive on land.
“It’s been known to be a problem in Northland and in kumera plantations for quite a while, but increasingly in Waikato and further south – there’s a lot of concern about it moving around.
“It’s not highly invasive like a seed-producing plant, but it is invasive within a property once it gets in due to its big rhizome (root stem) and the simple difficulty in controlling it.”
The plant is spread by vegetative reproduction, meaning just fragments of a living plant being moved from one site to another allowed it to spread.
“Also, the use of glyphosate has been noted to cause the plant to fragment and those fragments are not totally killed by the glyphosate and can be re-established.”
It could also be moved if it was established in a farm drain and floated down that waterway due to a weather event, re-establishing itself elsewhere.
Recently, the weed had been found in Taranaki, which was evidence that it is spreading.
It was also present in the Bay of Plenty where it had been found in kiwifruit orchards.
“They suspect its from the movement of some machinery or goods or services from orchard to orchard,” James said.
“Because it grows from the smallest of fragments, you don’t need much for it to be caught up in machinery or a pallet or something like that and be transferred from one orchard to another.”
James hoped the project would also reveal more information of alligator weed’s toxicity to livestock. James and his team will travel to places where anecdotally, livestock had been poisoned after eating the plant and speak to veterinarians.
They will also work with its industry partners including local government, Rural Contractors New Zealand and FAR to provide scientific analysis of their work to date where appropriate.
