Volume 42, Number 2 | JANUARY 19, 2016
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PRACTICAL PRODUCTION TIPS FOR THE PRAIRIE FARMER
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MANAGING GROUP 2-RESISTANT WEEDS IN PULSES ACROSS WESTERN CANADA Cleavers, mustard, kochia and sow thistle are among the weeds getting harder to control, but there are methods, starting with good agronomy By Lisa Guenther
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roup 2 resistance is something that is really a big problem across Western Canada,” says Dr. Chris Willenborg, a researcher at the University of Saskatchewan’s plant sciences department. Willenborg has worked on several research projects that inform weed resistance in pulses. The bad news is that resistance is spreading. And the more farmers rely solely on Group 2s as in-crop herbicides, the more Group 2 resistance will challenge us in the future, Willenborg says. But farmers still have tools left to manage resistant weeds in pulses. Read on to find out how to best use them.
Spot resistant weeds There’s no shortage of problem weeds in pulses. Cleavers are “top of mind” for growers in the black soil zone, Willenborg says. And Group 2-resistant wild mustards and kochia are also problems, he says. “Both of those tend to be problematic in the brown and dark brown soil zones. And a lot of that issue has not been helped with Clearfield varieties, in particular where we’re not necessarily managing the technology,” says Willenborg. Over 90 per cent of the kochia population sampled is resistant in Western Canada, says Willenborg, so farmers should treat all kochia as resistant. But with other weeds, resistance is more localized.
Willenborg says farmers shouldn’t give up on Group 2s with sow thistle, as resistance is patchy. Resistant cleavers are also spotty, but the problem is growing. Resistant wild mustard is a problem in southwestern Saskatchewan. Farmers will know if they’ve got resistant wild mustard in lentils if it “sort of looks like an intercrop with mustard. A lot of those fields, we can assume, have Group 2-resistant wild mustard.” If a herbicide fails, farmers should look first at the application, says Willenborg. For example, cleavers have a narrow application window, so the weeds may have been out of stage at spray time. Willenborg recommends scouting a couple of weeks after spraying to examine the weeds. If they haven’t been controlled or are coming back, the
photo: lisa guenther
» continued on page 4
Farmers check out pea plots during the Western Applied Research Corporation’s annual field day at Scott, Sask. Weed control is a perennial problem for pea producers.
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In This Issue
Wheat & Chaff .................. 2 Features . ........................... 5 Crop Advisor’s Casebook . 8 Columns ............................ 20 Machinery & Shop............. 30 Cattleman’s Corner .......... 36
Driving the big rigs
Susanna Heinrich page 17
Agritechnica
scott garvey page 30
FarmLife ............................ 41