Jack Keast using poison on weed growth. Biocontrol is an alternative to using chemicals and poisons on noxious weeds.
Jack Keast using poison on weed growth. Biocontrol is an alternative to using chemicals and poisons on noxious weeds.
A new biocontrol programme is soon to be released and it is hoped it will have far-reaching benefits for the Tararua district.
The programme is part of a national project aimed at controlling invasive weeds such as old man's beard.
Horizons Biosecurity officer Jack Keast said old man's beard, forwhich the scientific name is Clematis vitalba is a big problem in the areas he covers, around the Ruahine and Tararua ranges.
He also gives advice and information, as well as chemicals to help landowners control the weed.
Keast said the new biocontrol measure is a mite that, once it arrives on a plant, burrows into the vine and sucks the sap.
The mites create a colony and the plant responds by putting all its energy into trying to isolate the mites, rather than developing shoots or flowers.
"We're hoping that that will do enough damage to prevent old man's beard from producing seeds and minimising spreading and hopefully really knock the plants as well."
Flowering Clematis vitalba (Old man's beard) - its spread is a major headache for rural landowners.
The story behind this noxious weed is that it was brought out to New Zealand from Europe at some point during the early 1900s by a woman in the Rangitīikei, who had planted it over her outdoor toilet.
The plant had no natural enemies to help control it and it took off.
"Any plant in its natural range has natural enemies; herbivores or insects or diseases or funguses which will eat off it or live off it and keep those plants in some sort of balance."
Many of the plants like old man's beard had been brought in clean, with no diseases or pathogens.
"That's why things just go crazy in our climate because you haven't brought in those natural enemies."
Keast said the mite was brought over from Serbia by Manaaki Whenua (Landcare Research) and researchers inoculated old man's beard pot plants, testing to see if it would work.
Keast said the mite needed to be specific to that particular species of clematis, as there were some species of clematis native to New Zealand.
It also needed to not just eat the plant, but damage it as well.
The initial release of the mite would be in the Rangitīkei district, where the weed originated.
"It's a bit of poetic justice, really."
If the mite was successful in spreading and helping control the weed, it would then be shifted to the rest of the region.
"It can get into the wool of a sheep, (the farmer) can sell those lambs to another farm and all of a sudden you've spread it on that farm.
"And then a tractor comes in and cuts a bit of hay and then spreads it to the next one.
"All of a sudden you've got a massive infestation across an area, it's spread and you don't know those connections.
"You're not sure how it's got from one spot to the other, you can miss one of those spots and then you've got a massive loss of production."
The $3.2 million project is backed by the Ministry for Primary Industries' Sustainable Food and Fibre Futures fund, Landcare Research and the National Biocontrol Collective.
The project's governance group chair, Phil McKenzie, said biocontrol had the potential to provide a longer-term solution at a time when more registered herbicides were being restricted.
New Zealanders were also demanding more environmentally friendly farming practices.
While biocontrol was expensive upfront, the long-term benefits made it worthwhile, saving projected billions of dollars in costs such as labour, chemicals and loss of production.
