Growing soybean on high soil mineral nitrogen (N) fields, or when N fertilizer was applied in increasing rates, resulted in an increase in volunteer canola competition and a corresponding linear decrease in soybean yield. Research was conducted in Manitoba looking at the resource-ratio (R*) hypothesis. This...

Kochia with resistance to glyphosate was found at 78% of sites sampled, with 44% of sites exhibiting fluroxypyr resistance, and 28% with dicamba resistance. Triple resistance to Group 2 ALS inhibitors, Group 9 glyphosate, and one of the Group 4 synthetic auxins was found at...

Fall applications of flumioxazin, pyroxasulfone, and combinations of flumioxazin and pyroxasulfone to manage weeds emerging the following spring is a safe and effective weed management program in ultra-early seeded wheat. Ultra-early planting of wheat with a soil temperature trigger of 0-2.5 C has been shown to...

Yield losses caused by kochia competition are high, with mean losses reported to be 68% in grain corn, 62% in sorghum, 52% in soybean, 46% in sugar beet, 40% in silage corn, 23% in sunflower, 20% in spring wheat, 13% in canola and field pea,...

Layering Group 14 herbicides saflufenacil or carfentrazone + sulfentrazone pre-plant with a Group 2/6 imazamox/bentazon post-emergent treatment can effectively control glyphosate- and ALS inhibitor-resistant (Group 9 + 2) kochia in field pea. Layering will also help to reduce herbicide selection pressure through the use of...

A flax rotation that included 3 years of alfalfa with reduced herbicide applications provided similar wild oat and cleaver control as a flax-barley-flax-oat rotation with recommended herbicide applications. Including 2 successive winter cereal crops in a 5 year rotation also improved wild oat control. Wild oat...

Weed control has typically focussed on preventing yield loss with the side benefit of controlling weed seed return to the seedbank. This research proposes to turn that approach on its head by developing an understanding of when weed control is critical to prevent the return...

Early  crop topping treatment with a systemic herbicide targeted at panicle emergence had the largest impact on wild oat density, dockage, seedbank, and crop yield in the following year. An early, or a combination of early and late crop topping (at initiation of seed shed),...

A randomized-stratified survey of 315 sites in Manitoba found that, overall, 58% of the kochia populations tested were glyphosate-resistant, while 1% were dicamba-resistant. There was a rapid increase in glyphosate-resistant kochia over a five-year time frame, and the survey also confirms the first cases of...

Action and economic thresholds for volunteer Roundup Ready canola in Roundup Ready soybean were determined. Economic thresholds of less than 0.5 plants/ft2 (<5 plants/m2) highlight the highly competitive nature of volunteer canola in soybean crops. Volunteer glyphosate-resistant (GR) canola is a challenge for Roundup Ready soybean...

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