Questions of the Week

Is it verticillium stripe, sclerotinia or blackleg?

Scouting for disease can be easier at this time of year, as diseased plants may die prematurely and be clearly visible amongst the still living crop. However, differentiating between diseases can be challenging. Don’t scout from the road or jump to conclusions: walk the field, scout carefully and send samples to labs. Here are quick tips on how to tell verticillium stripe, sclerotinia and blackleg apart. CCC agronomy specialists and others can help with diagnostics. Free clubroot, verticillium stripe and blackleg testing is available in MB for MCGA members (more info here), and in SK through SaskCanola/SaskOilseeds (more info here).
(Identifying sclerotinia stem rot) (Verticillium stripe and blackleg)

Is that bug actually a problem (and can anything be done to manage it?)

There are many species of insects in the crop, some in relatively high numbers. Only a few will hurt the crop at this late stage. Scout carefully and regularly, especially for lygus bugs, diamondback moths and bertha armyworm. High grasshopper populations have been reported in some southern regions of both Alberta and Saskatchewan. Lygus threshold of 2-3 per sweep (20-30 per 10 sweeps) now applies to canola at late flower to early pod. Once past this stage, the crop should be tolerant of feeding. Bertha armyworm’s peak emergence was late this year and warm spots of adult emergence were found so scouting for this insect now should be a priority. Some cricket damage to pods has been reported, usually at field edges and localized. There are no thresholds or control products registered for crickets.  

CCC agronomy specialists are often asked how dry canola must be before pests stop eating it. Though the answer depends on the insect and the tissue the insect feeds on, some later-season insects with chewing mouthparts (ex: grasshoppers) will continue feeding until the crop is extremely dry, but fluid feeders like lygus and aphids can’t utilize the crop efficiently at this stage. (Prairie Pest Monitoring Update of the Week – August 9) (Canola Insect Scouting Guide) (Pest & Predator Field Guide)

Are the neighbours swathing way too early?

We are still at least a week or more away from correct swath timing in most areas. Though plants may be turning colour (which may indicate disease), seeds still need time to mature. Crack open pods to assess. Waiting until at least 60% seed colour change to swath improves yield and quality. Where fields show uneven maturity due to hail, disease, flower blast, etc., assess where the majority of the yield exists, then time swathing around that portion of the crop. If drought locks in green seed, delay swathing where possible.

Use the time while waiting on the crop to mature to: add a loss pan to the combine and review how to use it, add clippers and sample bags for disease scouting to the swather, clean and prep bins, and ensure the straw chopper is operating as it should – 2025’s success starts with effective residue management this harvest. 

Manage kochia now or wait for harvest?

Kochia is poking above the canola canopy in many fields, including some that haven’t had it in the past. It typically gets a foothold in low-lying, unproductive, saline and/or compacted zones. If it hasn’t yet gone to seed, mow the patch as soon as possible: this will be the last opportunity to manage patches easily before seeds are viable. If it has gone to seed, don’t combine through it: harvest around it, then manage the patch after harvest. (How to contain herbicide resistant kochia) (Test kochia escapes for glyphosate resistance) (Manage kochia resistance now)