Nationwide project offers hope in war against weeds
A coordinated national research project aimed at tackling 6 of New Zealand's most invasive weeds through biocontrol is expected to have far-reaching benefits for landowners and councils across the country.
The 3-year, $3.2 million project is backed by the Ministry for Primary Industries' (MPI's) Sustainable Food and Fibre Futures fund; Manaaki Whenua – Landcare Research; and the National Biocontrol Collective (the Collective) – a consortium of regional councils, unitary authorities and the Department of Conservation.
"There's no doubt about it – weeds are a constant source of stress for landowners," says Phil McKenzie, Chair of the project's governance group.
"Biocontrol has the potential to provide a longer-term solution at a time when more registered herbicides are being restricted by our export trading countries, weeds are becoming resistant to herbicides, and New Zealand society is demanding more environmentally friendly farming practices."
The project has 3 workstreams. These are to: advance biocontrol programmes for several high-priority weeds; monitor weed reduction in matured biocontrol programmes on productive land; and develop a partnership for sustaining investment in weed biocontrol.
The project will focus on Sydney golden wattle (Acacia longifolia), Chilean needle grass (Nassella neesiana), old man's beard (Clematis vitalba), woolly nightshade (Solanum mauritianum), Chilean flame creeper (Tropaeolum speciosum), and yellow flag iris (Iris pseudacorus).
By completion, the project aims to secure Environmental Protection Authority approval for the release of new biocontrol agents for at least 3 of these 6 weed species.
"Weeds are a major threat to New Zealand's natural and productive ecosystems, and they're costly to control," says Mr McKenzie.
"Through this project we aim to safeguard our environment and save landowners and councils money by finding smarter ways to reduce herbicides and the labour needed for weed control.
"Although biocontrol is expensive upfront to develop, collaborative cost-sharing models will make the development stage affordable – and the long-term benefits make it well worthwhile."
"We've got 15 regional councils co-investing in the project too, which enables regional priorities to be accounted for in selecting weeds to work on."
"Biocontrol can be a long-term, cost-effective and sustainable weed management solution," says Steve Penno, MPI's director investment programmes.
"By pooling our research efforts across multiple development streams, including adopting what's worked in previous biocontrol programmes, we'll be able to accelerate progress considerably.
"Farmers need more effective tools to manage these invasive weeds. To be able to eradicate or at least substantially reduce some of our most persistent weeds would be a huge win."
Unlike synthetic herbicides, biocontrol agents pose no risk to human health and are much less harmful to the environment. Biocontrol uses natural enemies to provide a continuous, perpetual and self-dispersing method for permanent suppression of weeds. In the long-term, once agents are established and self-dispersing, herbicide use can be much reduced – and even eliminated in some cases.
Biocontrol is the only feasible management approach for many weeds because it allows widespread protection. Once established, biocontrol agents are self-sustaining, making them a cost-effective long-term management tool, with benefit-cost ratios averaging 18:1. In contrast, herbicide or manual weed control at individual sites is short-term and expensive, which constrains the area that can be protected. Biocontrol is an environmentally friendly and socially acceptable alternative to herbicides.
Chilean flame creeper [JPG, 331KB]
Chilean needle grass [JPG, 32KB]
Old man's beard [JPG, 1 MB]
Sydney golden wattle [JPG, 672 KB]
Woolly nightshade [JPG, 1.2 MB]
Yellow flag iris [JPG, 458 KB]