How to improve early season weed management?
With early season weeds turning fields green across the country, it’s weed management ‘crunch time’. Effective early control is critical, as weed competition during crop emergence and early growth stages makes the biggest impact to ultimate yield. Maximize herbicide efficacy by optimizing every controllable factor:
- Ensure the tank is clean.
- Use an effective tank mix partner. Most acres should now be assumed to contain glyphosate resistant kochia.
- Where possible, get ahead of the drill. Smaller weeds are easier to control. Dust from the seeder will limit a pre-emergence herbicide’s efficacy in dry conditions. (Pre-seed burnoff tips for best results)
- Follow these tips for spraying in windy conditions.
What are the top reasons for poor emergence?
Every year, Canola Council agronomists get called out to assess poor stand establishment. Other than frost damage, many of the factors (or combinations of factors) contributing to weak establishment are preventable at seeding. Consistently, the main reasons for emergence issues include:
- seeding too deep (the CCC continues to recommend seeding canola at ½-1” as erring too deep is more common and costly than erring too shallow),
- Group 2 herbicide carryover damage,
- flea beetles (see below),
- seedling disease, especially in wet soil, and
- inconsistent seeding depth across the width of a seeder, especially with new or new-to-you equipment.
There is only one chance to seed well. Slow down. Get the rate and depth right. Make time to calibrate equipment regularly. Instead of seeding all cereal, then all canola, could there be a benefit this year to mixing up one’s seeding schedule (ie: cereals – canola – cereals – canola) to spread the risk? (Canola Calculator)
What’s the cost of a harrow pass?
Harrowing, discing and other soil disturbance can help manage residue (sometimes) and can stimulate a flush of weeds for the following herbicide application. However, it can also dry soil, cause straw clumping, reduce soil structure and porosity, cause billows of herbicide-limiting dust, spread spores from diseases like clubroot and verticillium stripe, compact the soil, and add seedbed variability. The risk of seedbed damage via harrowing is much higher for shallow-seeded canola than deeper seeded cereals and pulses. Ask: is harrowing accomplishing your goals? What role does harrowing play in the whole season’s bigger picture balance of efficiency, convenience, risk and ultimate production returns? (Residue management in the spring) (Seedbed preparation) (Field study: canola emergence based on wheat residue treatment)
Are you prepared for flea beetles?
Flea beetles are emerging and feeding, with heavy pockets reported in Southern AB, NW Saskatchewan, and the Red River Valley. Flea beetles chewing into volunteer canola now are a good reminder that they’ll be hungrily ready for the emerging crop. Warm weather will increase their activity. Seed shallow into adequately warm soil and a well-prepared seedbed to help the crop outgrow its most susceptible stage within the 3-4 week window of protection provided by seed treatment. (Canola seed treatments) (Plant establishment – seed treatments) (Flea beetle management tips) (Tips for a more integrated approach to flea beetle control)