Seeding is the priority for many growers this week, but fields with lots of big weeds should get a pre-seed burnoff with a high rate of glyphosate before seeding. The herbicide needs only a day or two to get down into the growing point of these large weeds, then the grower can resume seeding. The economic return will be higher than if the grower seeded over these large weeds and then took a chance on getting them sprayed before crop emergence.
Shallow seeded canola can emerge within 5 days under warm and generally moist soil conditions. And since growers need to leave weeds for a couple days to start growing again after the seeding operation, the window for post-seed/pre-emergence spraying is very narrow. With all the wind these days, that opportunity may never come.
Click here for more on weed control under wet conditions.