For canola fields that have not been sprayed this year, effective weed control may come down to one herbicide application 鈥� so make that application count.
Start by assessing the weed and crop stage situation in each field. Answers to the following questions can determine the course of action, including rates, tank mixes and more: How many weeds are present? How big are they? What species are they? What is the crop stage? What is the crop stage relative to the weed stage?
If weed population is greater than the crop population and weeds are more advanced or at the same stage as the crop, the highest available rate of herbicide may be required to provide the best weed control.
Know the weeds present, and know the herbicide rate required to truly control those weeds.
If you have a lot of grassy weeds in a Liberty Link canola field, you will want to tank mix clethodim with the Liberty (glufosinate) at a rate suited to the infestation level. Or, if it鈥檚 a Clearfield or Falco crop, you may want to spray grassy weed herbicide early and save the partner broadleaf herbicide for a second pass. Those partner products can only be sprayed once per season.
If cleavers are a problem, a tank mix with quinclorac may be recommended. When using a tank mix, pay attention to the mixing order. It often changes based on the products in the mix. Talk to your retailer or check with the company for the mixing order specific to your tank mix. This is often critically important to avoid clumping and other major issues.
And finally, if the crop is moving toward the end of its herbicide spray window, it鈥檚 most likely that the crop will be sprayed only once. Under such circumstances, maximize herbicide efficacy by putting together an effective tank mix, choosing the higher herbicide application rate, and spraying under good conditions.
For more details on rates, tank mixes and timing for each canola system, please search for the article 鈥淲eed control strategies for each HT system鈥� at canolawatch.org. While there, you can sign up to receive the timely Canola Watch email updates throughout the growing season.
Ian Epp is an agronomy specialist with the Canola Council of Canada. Email [email protected].
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