Questions of the Week

How to get tank mixing right?

Tank mixing can make economic sense and can provide options for enhanced management. However, some mixes are antagonistic, mitigating the products’ ability to control the target pests, causing injury to the crop, plugging nozzles, or leaving residue in the tank. Before tank mixing, ask: did I check the label? Do I need to do a jar test? What’s the right mixing order? Ammonium sulphate needs to be added to the tank before some herbicides. When opting to combine insecticide and herbicide, keep in mind that preferred nozzle sizes differ. So long as drift isn’t an issue, consider adjusting sprayer pressure to better accommodate insecticide applied via herbicide-sized nozzles. Growers have until Dec 2024 to comply with the new tank mixing policy from PMRA. (Sprayers 101: Right way to spray) (Herbicide resistance prevention) 

Thank goodness for rain. Now how to stay ahead of weeds? 

Many regions are grateful for recent or forecasted rain. However, moisture will bring a flush of weeds to acres that missed a pre-seed burndown. Given current warm temperatures, the window for a pre-emergent herbicide application will likely be past. If wild oats haven’t flushed yet, don’t wait: Liberty works well on small weeds and a clean-up application can be done on a second pass where necessary. Managing weeds when they are smallest is always beneficial; weeds that emerge after canola reaches the 4-leaf stage are mostly cosmetic. 

If rain causes further seeding or spraying delays, take advantage of the pause to give the sprayer a spa day. The next week or two is the most common time for crop injury due to sprayer tank contamination, especially from Group 2 herbicides. (See weeds, spray them) (Best tips for weed management)    

Why are we not yet in the clear for flea beetles?

Flea beetles are being reported sporadically across the Prairies, but at lower numbers than usual. Stay vigilant – it is still too early to assume flea beetles won’t impact significant acres.  

Those who opted for enhanced seed treatments should assess those products’ efficacy and economic return as canola emerges. Lumiderm offers excellent control of cutworms and some enhanced flea beetle control; Buteo Start offers enhanced flea beetle control but doesn’t target cutworms with its new active ingredient.  

Given lambda-cyhalothrin’s new restrictions, talk to your retailer and consider the strengths and weaknesses of alternate options. Pyrethroid insecticides are not recommended for application over 25C. On a hot day, an organophosphate might be a better option. (Flea beetle management tips) (Flea beetle preventative strategies) (Flea beetle findings that shape management choices)

How to manage a stagey crop?

Dry surface soil in some parts of the Prairies is resulting in inconsistent canola emergence and crop staginess. An inconsistent stand does add challenges to weed management and other management priorities. However, the window of herbicide application timing is quite broad. Typically, the crop evens out somewhat through the growing season.  

Flea beetles could hit a stagey crop in consecutive feeding flushes, which means higher plant density won’t necessarily dilute beetles’ feeding. As the seed treatment is often only effective for 3-4 weeks from seeding date, small later emerging canola would be at higher risk of flea beetle injury.  

The seeding deadline for crop insurance is early June. That said, don’t give up too easily on the already-seeded crop if you are debating reseeding. A uniform two plants per square foot still brings a 90% possibility of achieving expected canola yield. (How to work through the reseeding decision) (Saskatchewan Crop Insurance Corporation) (AFSC – Alberta)  (MASC – Manitoba)