Harrington Seed Destructor ACCORDING TO BREANNE TIDEMANN, a field agronomy scientist with Agriculture and Agri-Food Canada based in Lacombe, Alta., herbicide resistance is continuing to increase in terms of how common it is, as well as how challenging it is to manage. “With each new herbicide-resistant weed, herbicide options become more restricted. With wild oat as an example, we have biotypes on the Prairies resistant to group 1 and 2 herbicides quite commonly, but there is also resistance to group 8, 14 and 15 products. That really limits herbicide options,” she says. Tidemann and her colleagues have been exploring other avenues of control, chiefly a machine designed to destroy weed seed at harvest. Funding for the research, which started in 2017, is being provided by the Alberta Canola Producers Commission, Alberta Wheat Commission, Saskatchewan Wheat Development Commission and the Western Grains Research Foundation. “In my opinion, the answer to herbicide resistance isn’t another jug of chemical,” she says. “We need to use multiple methods of managing weeds, and to me, it only makes sense to start targeting the seeds. Why let surviving weeds — the ones most likely to have new resistance traits — put their seeds into the seed bank to be a problem next year? I think seed destruction could play a key role in managing herbicide-resistant weeds in the, hopefully, near future.” Ian Epp agrees. He says in addition to reducing the total number of weed seeds entering the weed seed bank, harvest seed management is also beneficial in reducing the spread of weed species, including herbicide-resistant weeds, within a field. “Combines represent one of the best dispersal mechanisms available to weeds,” says the Saskatchewan-based agronomy specialist with the Canola Council of Canada. “Seeds that enter the combine may be spread up to several hundred feet away from the initial mother plant, which for patchy weeds, or seeds from a newly-introduced herbicide- resistant biotype, represents an efficient method of establishing new patches and rapidly becoming a widespread field problem.” This may result, he says, in growers using otherwise too expensive or intensive ‘patch’ management strategies to The control of herbicide-resistant weeds through seed destruction. Seek and Destroy Speed of chaff movement is critical for the system to work best. Photo courtesy of Dr. Neil Harker. 34 | Advancing Seed in Alberta