Interview with Hugh Beckie (2:25 minutes)
From the Jan, 30, 2012 Issue of Agri-News
Weed resistance has been an issue in crop production for many years. Wild oats and a few other weeds have developed resistance to popular herbicides. Most producers are aware of this issue, but there are always herbicide alternatives being developed.
“Resistance to glyphosate, a chemical commonly known as RoundUp® is found in other parts of the world and in Canada,” says Harry Brook, crop specialist with Alberta Agriculture and Rural Development. “Alberta now has its first case of glyphosate resistance. It has been confirmed that there is glyphosate resistant kochia in southern Alberta. This should serve as a wake-up call to producers to use different herbicide groups when treating problem weeds. Failure to take this problem seriously will result in the loss of effectiveness of our most popular weed control products.”
Continually using the same herbicide or products from the same herbicide group, actually results in selecting for those plants that are either not affected or affected less by the active ingredient than other plants. By killing off susceptible plants, you set the stage for the resistant ones to thrive as all their competition is killed off.
“Herbicides that have one specific mode of action are most likely to lead to resistant weeds,” says Brook. “However, the most common reason for having resistance show up is due to repeated use of the same chemical. Glyphosate falls into this category.
“Over the last 20 years, the price of glyphosate has dropped to the point where it is relatively cheap. The move to conservation tillage and zero tillage relies heavily on using herbicides to control volunteer and early germinating weeds. Herbicide tolerant crops further encourage glyphosate use to the point where a piece of land could have three to four applications of glyphosate in a growing season. Short crop rotations and a lack of crop variety have set up the situation for herbicide resistance to show up in weeds. This has lead to glyphosate resistant kochia being found in Southern Alberta.”
Keep in mind that pesticide companies are having greater difficulty finding new products or modes of action that work as herbicides. The supply of new products to control problem weeds is not unending, and miracle cures rarely happen. Herbicide companies know about resistance, and they have partially dealt with the issue by combining different herbicides from different groups into one product. A lot of the “new” herbicides are only co-packs or premixed formulations of existing products.
“Combining products helps somewhat, but it does not address the real issue of specific herbicide overuse,” says Brook. “It may extend the life of a herbicide where resistance is developing, but it doesn’t solve the problem. There are also weeds that develop multiple resistance to a wide variety of herbicide groups and modes, the superweed.
“For example, group 1 and group 2 herbicides have been used extensively over the last two decades for wild oat control. Now, many producers are finding that they have resistance issues in their wild oats. In Manitoba, there are fields with wild oats resistant to three or four different herbicide groups. We are running out of herbicide options for wild oat control.”
This resistant kochia is Alberta’s first case of glyphosate resistance and the third weed with glyphosate resistance in Canada. It is evident that the way pesticides are used must change and the issue of resistance must be taken more seriously or producers will run the risk of losing some of their most useful tools for weed control.
“Pay attention. Watch your fields. Use a good crop and herbicide group rotation to keep this problem at bay,” adds Brook.
Contact the Ag-Info Centre or your local agronomist for more information.
Contact:
Harry Brook
310-FARM
