Hot and dry or hot and humid? Hot, dry weather should reduce the risk of heavy sclerotinia infection, even if moist weather earlier promoted a lot of apothecia emergence and spore release. Hot, humid weather that leads to morning dew and a humid canopy can promote the disease. Keep in mind that even thought the sclerotinia fungus does not like to grow over temperatures of 30°C, night temperatures are often lower and will allow for fungal growth. But also keep in mind that hot weather during flowering can increase flower and pod abortion and reduce overall yield potential. Hot, dry weather during pod fill and ripening also reduces the progression of sclerotinia within the plant.
While some areas are reporting higher numbers of diamondback moth larvae (shown above), it takes 100-150 larvae per square metre in immature to flowering plants or 200 to 300 larvae per square metre in plants with flowers and pods to cause enough damage to warrant a spray. Natural controls, including beneficial insects, tend to keep numbers below thresholds.
This article provides a review of thresholds for major insect pests of canola, as well as background on how they were established and how following thresholds can improve profitability.
A Canola Watch reader sent us this question: I have wild buckwheat at the 3- to 4-leaf stage that somehow got missed with the first application of Liberty 10 days ago . It’s moderate in severity. Will it cause me grief at swath timing? And or will it have any effect on yield? Crop stage is 6-leaf or so.
Wind and wet pushed back a lot of weed management and some fields are still not sprayed. In this situation, intense weed pressure can reduce yields by 20%, 30%, 50%… That’s why early weed control has a huge positive effect on profitability, but late control is better than nothing. Late control can stop the yield loss, stop weeds from contributing substantially to the weed seed bank, and improve crop harvestability.
These can be hard to tell apart sometimes. Pinched or otherwise damaged-looking stems can occur with all three. The photo shows blackleg infection. Here’s how to tell them apart…
Hot days (28-30°C and up) and warm nights (16°C and up) from bud to mid-flowering stages can have a significant effect on canola yield.
Flowering canola can, with enough time, recover from hail that knocks off a large percentage of flowers. Time and moisture are the best treatments.
The Canadian Agriculture and Food Museum opened its new exhibit “Canola! Seeds of Innovation” on July 1. Through the interactive exhibition, visitors can explore the story of the “made in Canada” crop.
Canola Watch is a free, unbiased, timely and research focused weekly newsletter from the Canola Council of Canada Crop Production Team
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