Topics for the week

Weeds: Fall-applied Edge, spraying after a 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.

Storage: Green chaff is a risk factor 

Frost can benefit straight combining because it softens green stems and makes for easier threshing. However, check combine settings and losses after a frost. Easier threshing can change the dockage scenario. Green dockage in the bin can increase storage risk because, while seeds may be dry, chaff may have higher moisture. Storage risk factors, including green dockage.

Seed: Ask about verticillium-resistant cultivars 

When researching canola cultivars for 2023, ask seed companies about differences in verticillium resistance. The trait is not officially offered but field observations do suggest differences in verticillium stripe severity among cultivars. Seed companies may have this information even though you won’t find it in brochures. Conversations with seed retailers can be a valuable way to gather information on the right canola cultivar for each field. Also ask about clubroot resistance, blackleg resistance, pod-shatter tolerance, seed treatment options and anything else that comes to mind. 

Plant counts: Why count stems in the fall? 

Use a post-harvest stem count to calculate canola survival and compare results to spring plant counts. By collecting a few years’ worth of plant stand data and cross-referencing it with seeding rate, yield, seed quality and maturity records, farms can determine their most economic target plant stands and seeding rates. Farmers and agronomists can enter fall stubble counts and re-calculate emergence at  Maps based on data from Canola Counts are in the Canola Encyclopedia