Grassy weed control in HT canola

June 10, 2015 - Issue 13

Some canola fields face intense competition from grassy weeds this year.

Intense competition from grassy weeds.

Grassy weeds are getting ahead of the canola in some fields. Timely weed control is essential.

Tips for grassy weed control in glufosinate resistant (Liberty Link) canola:

Liberty works best when applied with water volumes of 10 gallons per acre and when temperatures are warm. Most control issues for herbicides that rely heavily on contact activity, such as Liberty, are related to insufficient water carrier volumes or late staging.
If wild oats and other grassy weeds emerge before broadleaf weeds, it might be a good option to go in with a Group 1, then follow up later with Liberty. With heavy grass populations, the mix of Liberty plus Select or Centurion works well. If the grassy weeds have Group 1 resistance, then definitely make sure to increase the Liberty water volumes.

Tip for glyphosate resistant (Roundup Ready) canola:

Make sure you use the 180 ae/ac rate of glyphosate if you are going in early to control grassy weeds so you still have the option for a second pass if needed.

Tip for IMI resistant (Clearfield) canola:

Odyssey Ultra (Odyssey + Poast Ultra) provides the broadest range of grassy weed control for Clearfield canola. It controls grassy weeds up to the 6-leaf stage of the weed, and the application window is up to the 6-leaf stage of the crop. Odyssey Ultra has three active ingredients: Imazamox – Group 2, Imazethapyr – Group 2 and sethoxydim – Group 1. Between the 4-leaf/no tiller stage (Odyssey maximum stage) and the 6-leaf stage of grass weeds, the Poast Ultra component is carrying the bulk of the load for grass control. Any grasses that are already Group-1 ‘dim’ resistant will not be controlled beyond the 4-leaf stage. Weed biotypes with Group 2 resistance will not be controlled either. Another option for grassy weed control in Clearfield canola is Ares, but it contains only imazamox and imazapyr, not the Group 1 active.

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