Questions of the Week

To spray or not to spray late season flea beetles?

Flea beetles can look worrisome when they amass on late season canola plants. However, flea beetle feeding on canola in late summer is rarely an economic concern, as noted here. Once canola is past the 5.2 growth stage, it becomes resistant to injury from flea beetles. Even when seeds in lower pods are still green, significant yield reductions mau require flea beetle numbers to exceed 100 per plant (and in some cultivars, 350 per plant). If the beetles manage to chew through pods to the seeds, they typically target pods in the top of the canopy that contribute little to final yield. Still want to spray? If swathing is a week or less away, there are few control options available in the pre-harvest interval calculator. There is no data indicating that a pre-harvest insecticide this fall will reduce flea beetle feeding on canola seedlings next spring. (Late season flea beetles)

How much harvest loss is too much?

Now is a great time to prep the combine for harvest, including testing all settings. Calibrate with a goal of 1% combine loss: when losses are greater than this, final yield will be impacted; any less and the combine may be running too slowly to complete harvest efficiently . (Note: according to this 2019 study, average losses of canola at combining across Western Canada were three times higher than ideal, costing producers an average of $12.35/ac). Combine settings should – at a minimum – be adjusted between every field and according to conditions, taking shatter ratings into account. Onboard electronic loss monitors do not provide an accurate measurement of loss. Follow these instructions using the Harvest Loss Calculator to determine actual losses. Agronomists: is measuring harvest loss a service you could offer your clients? (Minimizing grain loss during harvest)

What decisions should be made now to best prep for harvest?

  1. Which pre-harvest product? A pre-harvest aid cannot even out or speed maturity but can speed dry down (diquat products), control perennial weeds (glyphosate), or support crop and weed dry down (saflufenacil).
  2. When to apply pre-harvest product? Check recommended timing and required pre-harvest intervals here. Cool, moist weather will slow dry-down.
  3. How much water? Use at least the minimum recommended amount of water (glyphosate: 5 gallons; Heat: 10 gallons; Reglone: 20 gallons) to ensure a pre-harvest product achieves necessary coverage. Heat and Reglone are contact products. If the goal is to manage weeds under a thick canopy, apply with additional water so droplets get through the crop stand.
  4. Swath or straight cut? Shatter tolerant varieties can offer harvest flexibility, but straight cutting works best in an evenly mature, dense, well-knit canopy with good pod integrity. (Canola harvest guide)
  5. When to swath? Maximize yield and quality by swathing when at least 60% of seeds on main stem show some seed colour change. (Canola swathing guide)

Disease scouting: are you considering incidence, severity and prevalence?

A disease’s impact depends on incidence (rate of new plants infected in a specific population over a specific amount of time), severity (how severe the infection per plant) and prevalence (percentage of plants impacted in a given population). Aster yellows can look extremely obvious and have a high severity (100% yield loss per infected plant), but so far this year appears to be limited to a low number of plants per field. Verticillium stripe, especially in southern Manitoba, is impacting a significant number of plants but at generally low severity. Though less shocking visually than aster yellows, sclerotinia and blackleg are costing significant yield in some fields: high crop density and long flowering promoted sclerotinia even in fields that were sprayed. Scout effectively to determine disease rates and estimate actual losses. Use this yield loss calculator for blackleg. Optimize scouting accuracy by pulling up and assessing 100 plants in a W shape disease scouting pattern: look at the root for clubroot, clip for blackleg, asses the stem for sclerotinia and verticillium stripe, look for abnormal growth patterns and empty/abnormal pods for aster yellows. Effective disease scouting is critical to timing swathing right: crop maturity can be overestimated as diseased and dead plants often appear dry and yellow. (Canola disease scouting guide) (Canola Watch video: disease scouting)

What funding is available through Canola 4R Advantage?

The CCC is now accepting applications for year two of Canola 4R Advantage, which provides funding to help pay for BMPs focused on nitrogen management, including soil testing, field zone mapping and enhanced efficiency fertilizers. As a reminder, growers have access to several enhancements in year two of the program, including the funding limit increase to $20,000 per eligible BMP per farm (up from $6,000 in year one). Find complete program details here.

Are you planning to apply for Canola 4R Advantage? Whether your answer is yes or no, let the CCC know by completing our short, four-question survey today.