AN integrated weed management approach that incorporates herbicide and non-herbicide tools is critical if growers are to manage hard-to-kill weeds, avoid costly, ineffective control measures and preserve the life of important herbicide chemistries. University of Sydney’s Weed Research program director Dr Michael Walsh said herbicide resistance was an escalating problem in the northern grain growing region. While growers in Queensland and NSW have traditionally faced fewer problems than their western counterparts, that’s rapidly changing, he said. Dr Walsh has played an integral role in developing one of Australia’s leading non-herbicide weed management tactics, harvest weed seed control (HWSC), which focuses on the capture and destruction of weed seeds. “Annual weeds such as ryegrass, wild radish, brome grass and wild oats have adapted to cropping systems, growing to similar heights as cereals and maturing at the same time,” Dr Walsh said. “HWSC plays an important non-chemical role in stopping weed seeds from entering the soil seedbank and can dramatically reduce the emergence of hard-to-kill weeds in the following season. “It involves collecting, destroying or burning weed seeds that are present at harvest and is particularly effective on problem species such as annual ryegrass and wild radish. There can also be a significant impact on the more difficult to collect species such as black oats, and brome grass.” A new tool to help growers incorporate HWSC into their weed management program is now available with the release of a GRDC Know More video explaining the use and benefits of HWSC. “Methods range from something as simple as a chute on the back of the harvester to more complex systems such as a mill system which is integrated into the rear of the harvester,” Dr Walsh said. “My advice to anyone just starting out is to start simple and assess how HWSC techniques can be effectively incorporated into the management program before advancing to something like the Integrated Harrington Seed Destructor, chaff carts or even a bale direct system. “By keeping weed seed loads low, growers can greatly reduce the risk of herbicide resistance development, and potentially protect the efficacy of important herbicide chemistries for decades.”
