Canola Watch: Delayed weed control | Top-dress podcast

Delayed weed control? Make it count

Some canola fields have not had a herbicide application in 2020. Pre-seed burn-off was skipped due to undesirable spray conditions prior to seeding. Early in-crop herbicide application has been delayed due to constant high winds and rain. For canola fields that have not been sprayed this year, effective weed control may come down to one herbicide application – so make that application count.

Assess the 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 higher 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’s 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.

And finally, if the crop is moving toward the end of its herbicide spray window, it’s 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. The full article has links, a table and more spray situations that are common this week.

 

In This Issue > QUIZ – Am I too late? Four scenarios with “Yes” or “No” answers on application timing. Think you can go four for four? TAKE THE QUIZ > PODCASTs – Macronutrient deficiencies and Top-dressing We have three new podcasts on fertilizer themes, including how to identify macronutrient deficiencies, tips for top dressing, and 4R designation for agronomists and farmers. LISTEN > Tip 1. Will canola recover from early-season hail? Even in severe cases, many individual plants may die but a whole canola crop is fairly resilient as long as a few plants survive per square foot. > Tip 2. Missing plants might be “slow” plants Many things can cause canola plants to go missing. Some plants are just slow…maybe due to soil conditions or deep seeding. After a hail, maybe these slow plants can make a contribution. > Tip 3. Insect update We have no major outbreaks to report this week, but include cutworms in the field scouting checklist, continue checking on flea beetles until crop reaches the 4-leaf stage, and put diamondback moth on the watch list. > Tip 4. VIDEO on seed-placed fertilizer check-up While doing emergence assessments, consider the effect of seed-placed fertilizer. This video provides a quick update on Warren Ward’s ON-OFF test. > Connections – Remembering Phil Thomas Phil Thomas was a former Alberta oilseed specialist who authored the Canola Growers Manual, which evolved into the online Canola Encyclopedia – a resource we use a lot in Canola Watch. Phil passed away peacefully last week. Thank you Phil. We’ll miss you. More connections.