Grainswest - Tech 2022

Tech 2022 Grains West 40 implications when we’re talking about glyphosate being one of the most relied upon herbicides in conservation tillage systems across Western Canada,” said Geddes. Other surveys also found Group 4 resistance in kochia and triple-resistant kochia biotypes have shown up across the Prairies. This type of resistance drastically limits herbicide options, said Geddes. In his work, Geddes examines new options for control of herbicide-resistant kochia in spring wheat. He has learned even some of the better control options for Group 2 and Group 9 herbicide- resistant kochia, such as synthetic auxins, may not be sustainable. He did find some Group 14 herbicides effective during burn-off, but some have little residual control. Geddes is concerned higher selection for Group 14 will occur as glyphosate resistance continues to grow. As resistance issues mount, Geddes said farmers will want to add non- chemical solutions to their management strategies. The most consistent tool that limits weed seed production is an increased seeding rate, he added. “You need to do whatever you can to promote a competitive crop that can help compete with those weeds.” Kochia seed production occurs around harvest. Using earlier-maturing crops enables farmers to get in the field sooner, thereby cutting off weed seed production. This allows for additional management tools. Kochia seeds, said Geddes, only remain viable in the soil for one to two years. “If you can prevent seed production for a couple years in a row, that goes a long way to depleting those populations,” he said. Various weeds require their own unique management strategies. As chair of the Resistant Wild Oat Action Committee, University of Saskatchewan research scientist Eric Johnson has done much work on wild oat biology. He’s found that since wild oat matures earlier, harvest timing tools are less effective. Launched in 2021, the committee is testing strategies to manage the growing problem. While this work is in its preliminary stages, the committee’s farmer members lead a series of projects to evaluate alternative control methods. Led by Nathan Eshpeter, the farmer group is evaluating tillage practices. These include inversion tillage, to determine if it can bury seeds deep enough to reduce their viability. The committee is also conducting a sampling program, working with fellow farmers who have never before tested wild oat fields for resistance. Johnson said they hope to evaluate the impact of winter-seeded crops such as fall rye to see if they can outcompete wild oat. In the meantime, he said, they will assess additional tools and techniques. These include increased seeding rates, layered herbicides and fall-seeded and short-term forage crops to promote competition. “We’ve proven that all of these things work,” said Johnson. “Part of the problem is farmer adoption. In some cases, they are using them, and in other cases things like short-term forages just don’t fit their situations.” Johnson said the plan is to evaluate interrow spraying and non-chemical solutions, such as the X-Steam-inator. Designed in Saskatchewan, X-Steam- inator is a sprayer that uses electricity to generate high-temperature steam on demand to kill weeds and terminate plant growth. So far, uptake hasn’t been huge. “We’re still in the infancy stage,” said Johnson. “They have a number of practices they can employ, but growers are looking for a broader suite of practices they can use.” Independent crop consultant Matt Gosling has worked with central Alberta farmers for 20 years in what he calls a “unique geography” in terms of herbicide-resistant kochia. On the 150,000 acres his consultancy covers, Gosling has found Group 2 and Group 9 resistant, as well as suspected Group 4 resistant kochia biotypes. But he also sees resistance issues in chickweed, which is particularly problematic as it flourishes in higher organic matter soil, even under a competitive crop canopy. Gosling asks farm clients if they have a plan B for when they find total or majority resistance to Group 1 and 2 herbicides in wild oat. Most don’t have an answer, he said. “My go-to rotation for Group 1, Group 2 wild oat resistance is barley silage, hybrid fall rye, Roundup Ready canola or Liberty, repeat,” he said. “It’s a three-crop rotation that involves silage, so you need a livestock enterprise within a few miles for this FEATURE “Roughly, we’re seeing about two new biotypes of herbicide- resistant weeds showing up in Canada each year.” —Charles Geddes