Topics for the Week

Missing flowers likely due to early environmental stresses

Canola growers from BC into Saskatchewan and even Manitoba are reporting aborted flowers and empty racemes (stems). After inspecting fields and consulting with plant physiologists, we believe the failure to flower and lack of normal pod development is caused by plants experiencing a hormone imbalance following early season environmental stress. Different stress factors or combinations of stress factors (from cold to heat to moisture challenges) likely caused similar symptoms in different areas. We are confident that symptoms noted in the fields and samples we have inspected were not caused by recent insect feeding despite lygus bugs and other insects being noted in some of the fields.

Favourable environmental conditions should alleviate the symptoms, but keep in mind that prolonged stress may require prolonged recovery. Growers should continue to actively manage their crop, basing crop input decisions on economic thresholds, soil test results, and expected return on investment. We are not aware of any crop protection or fertilizer products that can more quickly alleviate these symptoms. We will continue to investigate and report findings. (10 reasons for missing pods) (Multiple factors combined may cause missing canola flowers or pods)

Sclerotinia risk is now high

Conditions are currently ideal for sclerotinia development in many parts of the Prairies. High temperatures alone won’t protect canola from sclerotinia if adequate humidity exists under the canopy to keep the ground moist through the day. While pathogen development does slow after 30oC, apothecia arising from sclerotia can still release spores. Note: last year’s drought conditions won’t reduce sclerotinia risk this year as sclerotia can survive in the soil for four years or more.

Fungicide application must occur before disease symptoms are evident. Scout now, assess risk carefully, and be ready to apply fungicide as soon as necessary. If the crop is priced at $20/bu and the price of fungicide is $20/acre, then only four plants of every 100 need to be infected with sclerotinia in a 50-bushel crop to pay for the fungicide cost. Two fungicide passes may offer return on investment in long-flowering fields under high-risk conditions. (Sclerotinia fungicide timing) (Sclerotinia spray decision) (Precipitation map)

Insect management must-do’s

Bugs of all kinds will soon be marching into Prairie canola fields. Carefully assessing thresholds (where applicable), applying integrated pest management, and staying within product label recommendations are absolutely necessary to support farm economics, protect beneficials, maintain market access, and ensure environmental sustainability. Scout weekly during the growing season and more frequently when infestations approach economic levels or when weather conditions favour the rapid development of specific pests. Proper scouting technique matters, especially when it comes to sweep netting: here’s how. There is no threshold for lygus bugs at this time of year as researchers have found no link between early season lygus bug feeding and yield loss, likely because the crop compensates. For more information about specific insects and insecticide options, refer to the Field Crop Protection Guide.

Do add-ins add up?

Countless nutrient products and other crop additives are promoted as early and mid-season yield boosters and crop stress reducers. It can be very tempting to invest, especially in a year where many acres are suffering aborted flowers and poor pod set. The big question is: does that new or new-to-you product actually work? Look for reliable, unbiased, scientific data before investing. When trying any new product, start small: apply to just a few acres to determine return on investment. At the very least, leave a check strip to determine whether it helps or hinders the crop. (Quick tips for on-farm trials)