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 2 + 6) kochia in field pea. Layering will also help to reduce herbicide selection pressure through the use of...

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...

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...

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...

The most effective and consistent treatments for glyphosate-resistant (GR) kochia management included Authority (sulfentrazone) applied pre-emergence, post-emergent Enforcer D (fluroxypyr/bromoxynil/2,4-D) at the high label rate, and post-emergent Infinity (pyrasulfotole/bromoxynil). Glyphosate-resistant (Group 9) kochia has rapidly spread across Alberta since it was first discovered in 2011 in...

Effective pre-emergent or pre-emergent followed by post-emergent (two-pass) programs tested in this research on the U.S Great Plains should be proactively utilized by growers to manage glyphosate/dicamba resistant kochia in Roundup Ready 2 Xtend (glyphosate/dicamba-resistant) soybean. A similar approach may prove useful for western Canadian...

Time to 90% loss of glyphosate-resistant kochia seed viability averaged less than 8 months. Short seedbank longevity, delayed and reduced germination, and delayed time to first leaf of glyphosate-resistant kochia can be used to develop weed control strategies. Kochia herbicide resistance continues to spread across the...