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What to do after late season hail?
Canola plants damaged by hail this late in the season will no longer successfully recover lost yield. Managing the crop post-hail is often an unfortunate choice between harvesting green seed or losing yield to bruise-induced pod shatter. As hail pressure can be localized and the full extent of damage can take several days to appear, scout well and frequently following a hail event. Where possible, wait to swath a hail-damaged but immature crop, especially if bruising/damage is limited to less productive upper pods. Some pod drop/shatter may be preferable to losing both yield and quality by swathing before the highest-yielding (mid-canopy) pods reach 60% colour change. More tips on post-hail decision-making are available here.
Insect update: Diamondback moths
Diamondback moth larvae numbers are increasing across much of the Prairies, not surprising given that they can produce each subsequent generation in as little as 21 days. If the number of pests shaken from a ft2 collection of plants exceeds the 20-30 larvae/ft2 economic threshold, use the spray-to-swath calculator to ensure an adequate pre-harvest interval (PHI) remains before harvest (and consider natural enemy presence) before applying insecticide. Visit Keep it Clean for more information on the importance of PHIs. (August 12th PPMN update – scroll to article 3 for predicted diamondback moth development)
Diamondback moths around the world have a high potential to develop insecticide resistance, though no resistance has yet been confirmed in the Canadian prairies. The jetstream may bring diamondback genetics pre-selected for resistance, so always confirm that insecticide is working once it’s safe to re-enter the field.
Patience pays at swathing
“The single best thing that most canola growers can do right now is not swath yet,” says CCC agronomy specialist and harvest lead, Shawn Senko. While it can be challenging to wait until seeds achieve 60% colour change, patience pays in both quality and yield. NDVI imagery may help improve swath-timing decisions, and early season imagery can help predict yield. (How to use technology to manage yield) (Pre-harvest aids)
While waiting, now is a great time to prepare the combine for low-loss harvest:
• Calibrate settings. Set the monitor to the recommended setting for canola, then check to ensure a bolt or feeler gauge of the same size as the setting slides snuggly between the grooves for both sieves and concaves. If not, follow instructions in the user manual to calibrate.
• Book an in-field visit from the combine dealership. The cost of a visit is worth the investment if it achieves more refined settings and lower losses.
• Buy a drop pan and learn how to use it.
(Podcast: Combine stripper header)
Select seed for better disease control
When selecting cultivar options for next year, consider which disease tolerances are most critical by region and especially by field. Remember that the “Big 3” diseases (blackleg, sclerotinia stem rot and clubroot) are almost exclusively determined by each field’s cropping and disease history. Let us emphasize and reemphasize again: Don’t join the clubroot club. Only buy clubroot resistant cultivars. (Use clubroot resistant canola early to keep spores low) (Choose the right cultivar for each field)
While it may be too early for a conclusive blackleg assessment in this year’s stand – the ideal timing to assess blackleg is at 30% seed colour change – do early (extra) scouting to get a feel for whether alternate resistance is necessary for each field in your cropping cycle and how that might change a future year’s cultivar selections. (Blackleg yield loss calculator)