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Pre-seed herbicide application important tool

Apr. 29, 2016 - A number of public weed surveys show us that herbicide resistance is an ongoing concern for Western Canadian growers. Glyphosate (Group 9) resistance and Group 2 resistance is continuing to spread and causing concerns for growers. There are 19 resistant weed species in Saskatchewan alone, 23 in Alberta and 19 in Manitoba (source: Hugh Beckie, Agriculture and Agri-Food Canada).

In managing herbicide resistance, growers should be mindful of the different stages for controlling weeds within the span of the growing season. Pre-seed weed control can sometimes be overlooked and is a key consideration.

"We recommend growers tank-mix their glyphosate to improve their pre-seed herbicide application and help delay the onset of resistance," said Danielle Eastman, brand manager for western herbicides and Clearfield at BASF. "Heat LQ, a Group 14 chemistry, is a unique active for cereal growers that can be applied at higher rates for residual suppression of flushing weeds including volunteer canola and will help control other resistant weed species such as kochia and wild buckwheat. Heat LQ tank-mixed with glyphosate applied pre-seed in cereals is going to provide broadleaf weed control in as few as three to five days (depending on active growing conditions), cleaning up those fields for cereal crops to emerge."

Dennis Connor lives North of Beechy, Sask. and has learned the importance of adding another mode of action with his glyphosate to combat resistance build-up on his farm. "Narrow-leaved hawk's-beard and resistant kochia have become a problem on our farm and we feel it's important to have a second mode of action on these weeds. Heat LQ added to the glyphosate is a powerful tool. It smokes these weeds very quick and our farm is mostly under control now."

Quick pre-seed weed control can help knock out resistant weed competition. "The other advantage with Heat LQ is how fast it works in the field. The weeds are crisp in like three to four days and you know we've got them under control. We like the performance," added Connor, noting this gives his field a clean start to the season. That's an important part of managing and mitigating weed resistance.

Eastman noted that crop protection companies like BASF continue to bring new chemistries to the market and recommend growers tank-mix their chemistries with multiple effective modes of action with herbicides active on the same target species to get the best results while managing herbicide resistance.