A new approach to weed control

The EH Graham Centre for Agricultural Innovation, an alliance between NSW Department of Primary Industries and Charles Sturt University, has been successful in obtaining funding for a three-year project valued at $580,000 through the Grains Research Development Council (GRDC) for research into managing weed populations and combating herbicide resistance in southern NSW.

Professor Deirdre Lemerle, Director of the Graham Centre, said that the project would investigate combinations of non-herbicide strategies to manage pasture and cropping weeds in southern NSW farming systems.

“The development of herbicide resistance in our major problem weeds has forced a rethink on weed management strategies, and growers need to be aware of the effectiveness of weed control throughout the life-cycles of the weeds, from seedling emergence to seed-set, with the ultimate goal being to prevent weeds carrying over to the next season.

“Growers have come to rely heavily on herbicides, but chemical companies cannot keep coming up with an effective alternative once a herbicide breaks down,” she said.

The project team, including Project Leader Hanwen Wu and Technical Officer Eric Koetz, will work closely with farmer groups, agronomists and consultants to investigate the impact of management strategies on weed population dynamics, the economic consequences of managing herbicide resistance and also to identify emerging weed threats.

A herbicide resistance survey across central and southern NSW will identify the current spread of herbicide-resistant weeds, in particular annual ryegrass, wild oats and wild radish.

The project will evaluate new and existing integrated weed management strategies for southern NSW and raise awareness of the impact of the strategies on seed bank dynamics and herbicide resistance.

A recent GRDC survey identified that 79 per cent of grain grower’s rate herbicide resistance as one of the major factors likely to impact on the profitability of their future cropping programs.

“This project will provide farmers with guidelines on what strategies or combination of strategies are most effective in controlling in-crop weeds and depleting the seed bank,” Professor Lemerle said.

“By using a combination of strategies growers will not only reduce reliance on herbicides, they will be reducing the pressure on development of herbicide resistance in our major weed populations and prolong the life of the cost-effective herbicides.”