By Cory Jacob, PAg, Provincial Specialist Oilseed Crops and Clark Brenzil, PAg, Provincial Specialist Weed Control
If you missed your pre-seed burnoff application, use the flexibility offered by your herbicide tolerant (HT) canola's herbicide system to maximize the benefit to your crop.
This spring has been challenging with dry and cold conditions that have impacted crop and weed growth, while an abundance of windy days has slowed spraying operations. Some farmers were holding off on a pre-seed herbicide application or haven't been able to due to a lack of weed growth, weed presence or frost and wind. This will mean that large winter annual weeds are now growing within newly emerging canola and competing aggressively for nutrients, water and sunlight. This can result in yield loss to the crop
Fortunately, producers have the option to apply a second in-crop herbicide s in glyphosate or glufosinate-tolerant canola to mitigate weed competition. Early application of the second pass in the two to four leaf stage of canola will provide the best balance of preserving yield and managing late-emerging weeds. Several research studies have shown that weeds emerging beyond the six leaf stage are unlikely to reduce yields. Truflex glyphosate tolerant canola allows for the use of higher glyphosate rates than Genuity glyphosate tolerant canola for managing larger and more difficult to control weeds.
Double in-crop herbicide applications are not available to producers growing Clearfield canola as those are one application per year herbicides. However, application of a product like Ares SN provides some soil residual activity and may achieve the same end as a double application of herbicides for use in glyphosate or glufosinate-tolerant canola, so application as early as possible is still advised.
Liberty 150SN is registered for three application of 1.6 L per acre each in glufosinate-tolerant canola, allowing applications to take place at ground crack, the two to three leaf stage and the four to six leaf stage.
Double in-crop herbicide application allows the producer to apply two applications while canola is vulnerable to avoid significant yield loss due to emerged and emerging weeds. This approach uses an early application as the crop is emerging to suppress or control large winter annual weeds that have emerged ahead of the crop, while also using a second, follow up application, at a more typical in-crop staging. This can take care of any weed flushes after the first application or of perennial weeds. Please refer to the 2020 Guide to Crop Protection for information about each herbicide-tolerant canola system along with herbicide rates for double applications and weeds controlled.