Questions of the Week

How much of a difference does patience make leading up to swathing?

Canola achieves optimum seed yield and quality when swathed at or after 60% colour change (SCC). According to an AAFC study, canola swathed at 60-70 per cent SCC yielded 11 per cent more than fields swathed at 30-40 per cent It takes approximately 10 to 15 days for canola to mature from the very beginning of SCC to 50-60% SCC. Pod colour is not a good indicator of seed colour: use this guide to correctly assess seed colour change. (Assessing seed colour change) (Swath later for higher yield)

What are four decisions to make now to be ready for harvest?

1. Swath or straight cut? Consider: is the crop even? Where is the primary yield? Is it a shatter tolerant variety? If the crop has variable maturity due to hail damage, disease, heat stress, etc., or if getting the crop down quickly is a top priority, swathing may be the preferrable option. If straight cutting, wait until 10% seed moisture for superior grain yield (as shown in this research).
2. Which pre-harvest aid(s) best suit the field’s weed control and desiccation needs? No product will speed up or even out a crop’s maturation, but pre-harvest aids can support crop dry down (diquat products), control perennial weeds (glyphosate) or promote both crop and weed dry down (saflufenacil). Always check pre-harvest intervals and proper timing for pre-harvest glyphosate application.
3. Is infrastructure ready for harvest? Now is the time to clean and calibrate all equipment and prep bins to receive the crop. Here’s how.
4. Is water quality adequate for pre-harvest glyphosate? Drought may cause increased salinity and other precipitates in dugouts. Water quality can impact herbicide efficacy, especially glyphosate is particularly sensitive to hard water. Consider testing water and look for alternate sources where necessary and possible

How to check the crop quickly?

Drive-by scouting is not recommended but a few tips can speed up the scouting process this time of year. Look for: 

• Patchy fields: distressed plants often die early and, if in patches, may be easily noticeable even from a distance. Here’s what to look for. 
• Holes in leaves / missing leaves: various diseases and pests can result in damaged, pockmarked and missing leaves. Bertha armyworm consume leaves from the base of the stem upwards.  
• Chewed pods: this link provides identification advice and thresholds for various pod-eaters.
• Flower / pod gaps: Flowers can abort for many reasons. This guide can help assess whether gaps are caused by heat blast, moisture stress, late off-label herbicide application, spray drift, tank residue, male sterility, nutrient deficiency, hormone imbalance and/or insect feeding. 

Why start pre-harvest disease scouting now?

The single highest priority at this time of year is disease scouting. That priority will only increase as we get closer to 60% seed colour change, which is the most critical time of all for disease scouting. Sclerotinia should be top of mind in areas with adequate moisture and has been reported this year in some fungicide-treated fields. When the crop is full height but still green, start looking for verticillium stripe’s characteristic ‘striped’ or two-toned, half healthy and half dry stem. There have been some reports of Alternaria and aster yellows (AY). We are gaining more understanding of AY, including that dandelion and sow thistle are part of the AY disease cycle, but we do not yet have best management recommendations available. (Tips for pre-harvest scouting) (Start your pre-harvest disease scouting) (Canola disease scouting guide)

Free disease testing:

Saskatchewan: SaskOilseeds (previously SaskCanola and SaskFlax) is once again offering free disease testing for clubroot, blackleg and verticillium stripe. More information is available here. Need to brush up on your disease ID skills? Take part in one of three free disease training workshops Aug 28, Sept 5 or Sept 12.

Manitoba: the Pest Surveillance Initiative (PSI) lab has offered free clubroot testing since 2014. The Manitoba Canola Growers Association lab offers free blackleg and verticillium stripe testing.