Weeds: Fall-applied Edge, spraying after frost
Edge: Farms grappling with glyphosate-resistant kochia, excess cleavers as well as herbicide-resistant wild oats and green foxtail may want to consider Group-3 ethalfluralin (Edge) applied this fall on fields planned for canola in 2023. The granular herbicide goes on with a Valmar or spreader, and must be worked into the top 1/4” to 1/2” of soil. Light harrowing in the fall is often enough, ideally at a right angle to the planned seeding operation. Ethalfluralin works through root and hypocotyl uptake prior to weeds emerging in the spring, so it needs to be in the soil. It can also be susceptible to losses from volatilization and/or light degradation if not incorporated properly. This article has a table with herbicides for fall application on fields planned for canola in 2023.
Frost: Wait for weeds to start growing again before spraying herbicides after a heavy fall frost. Frost has the bonus of killing annuals and may prompt another flush of winter annuals. Flixweed, a big moisture user, is one notable target for a late-fall herbicide application.
