Thursday, 19 August 2021 09:55

Growing concern over herbicide resistance

Written by  Staff Reporters
AgResearch senior scientist Trevor James. AgResearch senior scientist Trevor James.

Herbicide resistance is emerging as a serious and growing threat to New Zealand's food production, with recent surveys by scientists finding half or more of arable farms in some regions have weeds resistant to commonly and used herbicides.

AgResearch scientists, who are carrying out the first systematic approach to surveying for herbicide-resistant weeds in arable crops with funding from the Ministry of Business, Innovation and Employement, say the results they are seeing are often many times the levels of resistance that had been expected.

In additionm new resistant weed species are also being brought forward, or discovered by the AgResearch scientists working alongside the Foundation for Arable Research (FAR) and the Bragato Research Institute, as part of the Managing Herbicide Resistance programme which began in 2018.

Herbicide-resistant weeds were first detected in New Zealand in 1979, but until recently reporting of herbicide resistance has largely been ad hoc and left to growers and rural professionals to recognise and alert researchers.

AgResearch senior scientist Dr Trevor James, who spoke last week at the NZ Plant Protection Society's annual conference in Napier, says the survey findings are a wake-up call and should be focusing efforts to manage the threat of herbicide resistance.

"The issue is that as this resistance grows, so too does the costs and impacts on farmers and crop production in New Zealand.

"We firstly need to understand the full scope of the problem across New Zealand, the mechanisms involved in the resistance, how the resistance is passed through the generations of these plants, and then we need to look at strategies to address it and slow the development of the resistance," James says.

"At present, there are limited alternatives to many of these herbicides that the weeds are evolving resistance to, and that is an area that also deserves attention and investment in the research."

In 2019, a survey took seeds from 48 randomly selected arable farms in central Canterbury and weeds resistant to Group A and B herbicides were identified from a quarter of those farms.

Further surveying across arable farms in Southland, Waikato and Bay of Plenty found at least 50% had weeds resistant to Group A and/or B herbicides, with glyphosate being a problem in vineyards. The highest risk weeds were pasture-related grasses.

Common resistant weed species being identified by the researchers include ryegrass, wild oats and chickweed, as well as first time finds of resistant sow thistle (puha), summer grass, prairie grass and lesser canary grass.

More like this

Milk-based replacers better

Recently published research suggests that farmers should avoid feeding milk replacers with vegetable proteins and fats to lambs in their early life.

Future-proofing NZ's sheep

Beef + Lamb New Zealand Genetics' Low Input Sheep Progeny Trial is identifying the genetics that will future-proof this country's sheep industry.

Promising early results for facial eczema test

Early results from a pilot study investigating the potential for a laboratory test to determine facial eczema (FE) tolerance are positive, paving the way for more detailed investigation.

National

Why should we do more?

OPINION: Managing our dairy sector's impacts inevitably attracts a range of views. Should we do more, less or stay the…

Cattle sale with a difference

Innovation, loss and resilience have brought the Singh family to the point where it is poised to honour its patriarch,…

O'Connor's overseas odyssey

Agriculture Minister Damien O'Connor continued his overseas odyssey in the past week with multiple meetings in the US, Europe and…

Machinery & Products

Protective tint

Now available in New Zealand, Wildcat Static Cling Tint adds a protective layer to the windows of your tractor, harvester…

New owner for stoll

German company Stoll, the well-known manufacturer of tractor front loaders and attachments that claims to be the second largest producer…

Fert spreaders get a revamp

Kuhn has updated its MDS range of fertiliser spreaders, giving farmers more options to upgrade machines as situations change, rather…

Mowers spring into action

With spring upon us, thoughts turn towards shutting up paddocks for conservation and maybe the purchase of new machinery to…

» The RNG Weather Report

» Latest Print Issues Online

Milking It

Feeling the heat

US dairy farmers have a new threat to their business - heat waves.

Class action

The news has gone from bad to worse for a2 Milk - the company Synlait had hitched its wagon to.

» Connect with Dairy News

» eNewsletter

Subscribe to our weekly newsletter