The Weekly Advertiser Horsham

Throwing a net over mobile weeds

- BY CINDY BENJAMIN, WEEDSMART

Similar to feral animals, ‘mobile’ weeds move easily across landscapes, taking no notice of boundary fences, land use or land tenure.

These weeds are now the subject of a pilot area-wide management project to trial co-operative and cost-effective methods to reduce the movement of these weeds and the herbicide resistance traits they have evolved.

The cross-industry project has Federal Government funding to target weeds that are a common problem to all industries in an area and have mobile seed and pollen – that is, they spread easily.

Weed species that fit the criterion include flaxleaf fleabane, feathertop Rhodes grass and annual ryegrass.

In three distinct regions – in the Darling Downs of Queensland, the Riverina of NSW and the Sunraysia in Victoria – project teams are devising and implementi­ng area-wide management programs to tackle target weeds of concern in their region.

The University of Adelaide is providing targeted herbicide resistance testing within the pilot areas and mapping the spread of weeds, based on genetic testing conducted at the University of Queensland.

Dr Rick Llewellyn, senior principal research scientist – agricultur­al systems with CSIRO, is leading the area-wide management for cropping systems weeds project to better understand the importance of weed mobility, and test the opportunit­ies for this collaborat­ive approach.

He says the idea is to draw together industries and land managers to ‘find a collaborat­ive solution to a common problem’ where a strong value propositio­n can be establishe­d.

“Area-wide management has been very effective in the management of invasive animal pests and for some mobile insect pests,” he said.

“We know some weeds are particular­ly good at moving across the landscape, either as contaminan­ts or borne on the wind or in flood water – and most farmers have experience­d a weed incursion from a source beyond their farm boundary.

“We are testing collaborat­ive and cost-effective ways to reduce the spread of cropping weeds across diverse farming landscapes.”

Each of the three pilot areas has identified the highest priority mobile weeds to target in its initial on-ground project.

In Sunraysia, Mallee Sustainabl­e Farming and horticultu­re organisati­ons have partnered to develop strategies that minimise spray drift while also providing effective control of important weeds like fleabane. The University of Adelaide’s Dr Chris Preston is helping the Sunraysia project team as it investigat­es applicatio­n techniques and product choice for summer weed control in this diverse cropping region.

“Where a range of different crops are grown in close proximity there is a risk of damage through off-site movement of herbicides,” Mr Llewellyn said.

“To reduce this risk, growers using some products, such as phenoxy herbicides, must work within narrow applicatio­n windows; but to prevent large population­s of weeds setting mobile seeds, growers need cost-effective herbicide options.

“The area-wide management trials led by Mallee Sustainabl­e Farming compared weed fallow control efficacy of six alternativ­e products registered for use in optical sprayers, as well as options for better control of mobile and resistance-prone weeds like sow thistle in horticultu­re.”

The ‘Weedsmart Big 6 tactics’ can be applied to area-wide management as well as within a cropping enterprise to tackle resistance through strategic patch management and diverse control methods that result in low weed densities and prevent seed set of mobile weeds.

Mr Llewellyn said more co-ordinated awareness and informatio­n sharing could channel effort and innovation into weed-management improvemen­ts that benefited the individual land manager as well as the district.

“There has been an increase in the diversity of food production industries in many districts over recent decades, so there’s more and more opportunit­y for a collaborat­ive approach to reduce weed costs and risks as ‘new neighbours’ become establishe­d in many dryland grain growing areas,” he said.

The project involves a variety of research and developmen­t partners and has Federal Government support.

People can visit website www. weedsmart.org.au for more informatio­n about diverse weed control tactics.

 ??  ?? Dr Rick Llewellyn
Dr Rick Llewellyn

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