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In a 2017 Alberta survey, 13% of the kochia populations sampled were fluroxypyr-resistant. Only 4% of the populations were both fluroxypyr- and dicamba-resistant, indicating that different mechanisms may confer resistance to these herbicides. When combined with estimates of dicamba resistance, about 28% of kochia populations...
Weed surveys show that the incidence of herbicide-resistant grassy and broadleaf weeds continues to increase across the Prairies during the survey periods of 2014 through 2017. The perceived cost of herbicide resistance was estimated at $13.36 per acre. Regular surveillance for herbicide-resistant (HR) weeds has been...
Control of glyphosate-resistant kochia was achieved with the use of effective tank-mixtures utilizing Group 4, 14 or 4+19 herbicide groups. But the confirmation of Group 4 resistance in kochia highlights the need for careful herbicide stewardship to prevent further selection of multiple herbicide-resistant kochia. In 2011,...
All 15 PRE followed by POST herbicide combinations provided better control of volunteer canola compared with the glyphosate-only control, but tribenuron (i.e. Express SG) followed by bentazon, and tribenuron followed by imazamox plus bentazon (i.e. Viper ADV) provided solutions that were low cost, registered in...
Based on wild oat seed viability, early clipping of wild oat panicles before seeds are viable, in short-statured crops, may become a valuable tool for integrated wild oat management. Wild oat is one of the most problematic weed species in western Canada due to widespread populations,...
Trends in herbicide resistance management over the past decade were identified and include renewed efforts by the agrichemical industry in herbicide discovery, cultivation of crops with combined (stacked) HR traits, increasing reliance on pre-emergence vs. post-emergence herbicides, breeding for weed-competitive crop cultivars, expansion of harvest...
A kochia survey in southern Alberta in 2017 found that all kochia populations were resistant to Group 2 ALS inhibitors, 50% of populations were resistant to Group 9 glyphosate, and 18% of populations resistant to Group 4 (dicamba) herbicides. Kochia populations with triple resistance to...
Of 45 Russian thistle populations tested from central and southern Alberta in 2017, 31 (62%) were Group 2 (ALS inhibitor) resistant. No populations exhibited resistance to Group 9 (glyphosate). A random survey of Russian thistle was conducted post-harvest in fall, 2017. A total of 45 populations...
Field trials found pyroxasulfone (Focus), pyroxasulfone + flumioxazin (Fierce), and pyroxsulam (Simplicity) provided effective control of Japanese and downy brome in winter wheat. Trials were established at Lethbridge and Kipp, Alberta, and Scott, Saskatchewan, over three growing seasons to compare herbicides for control of downy and...
Herbicide screening studies on triallate-resistant (Group 8) wild oats found cross-resistance to Group 1 and Group 2 herbicides. Additionally, unexpected resistance to Group 14 and Group 15 herbicides was found even though the wild oats had never been previously exposed to these herbicides. Two relatively new...