Erin Brock, CCC agronomist for the Peace region, took these photos in early May. From a distance, this stubble looks ready for seeding. Scouting gave a more realistic perspective: a significant weed population had already emerged. Growers should take a close look at the weed spectrum and stage in each field prior to planning their early season weed control. It may be worth controlling those weeds before seeding, since early emerging weeds out-compete young canola for nutrients and moisture and can significantly reduce yield potential. For more, click here for a Canola Council of Canada factsheet on the benefits of early weed removal. Also read the latest Canola Watch newsletter.
Refer to product labels, company representatives or the provincial guides to crop protection for application rates based on the size and type of weeds present. Also, this time of year, frost damage will impede herbicide uptake. After a hard frost, wait until weeds start growing again and daytime temperatures warm up before spraying. Again, check labels for specific instructions.

Consider herbicide carryover

Many growers decided this spring to increase their canola acres. That means canola is often going on fields not planned for canola when growers did their herbicide applications last year. Canola going on to pulse stubble, for example, raises the possibility of imazethapyr carryover. Read this PDF for the complete list of herbicides and the carryover considerations for each.
2010 recropping and residual herbicide considerations.pdf