Look for the following agronomy articles in the March issue of Canola Digest magazine, which should be in mail boxes soon.
In one case, a canola field was showing clear signs of herbicide damage, and it appeared at first to be worse where the sprayer did its first two rounds. Upon closer inspection, the damage was only on two sides and both of these sides were alongside cereal fields owned by the same neighbour. The neighbour had applied the same new herbicide to both fields on the same day, and drift damage came in from both directions. The key diagnostic message in this case: Look beyond the damaged field when faced with a question that has no obvious solution. In the other case, a few canola cotyledons scattered throughout a field showed a strange halo effect with yellowing around the leaf edges. With help from the seed company, this damage was determined to be a reaction to the seed treatment, and as expected, the plants grew through the effect with no apparent damage. Key message: Consider every possibility when diagnosing a problem, but in the end, sometimes going back to the company rep or any product retailer can draw a quick conclusion to any concern.
The article provides management tips for canola volunteers with a combination of herbicide tolerance traits. Here is a quick summary:
—Treat volunteer canola as a weed and get rid of it.
—Growing at least one and preferably 2 or 3 crops between each canola crop can greatly reduce the volunteer population.
—Cereals provide a broad range of pre-seed and in-crop herbicide options for any type of canola volunteer. Stacked volunteers, even if they happen to have all three traits, are still susceptible to common herbicides, including 2,4-D and MCPA, and various new products. Group-6 Basagran can control all canola volunteers in peas, flax, beans and other broadleaf crops.
—CleanStart and Amitrol 240 are registered for pre-seed application before canola, providing alternatives to straight glyphosate.
—Keep detailed notes on herbicides and herbicide-tolerant systems used on each field.
—Leave canola seeds on the soil surface after harvest. If you use fall tillage, delay it until a few weeks after harvest.
—Apply herbicides early. Spraying volunteer canola at the 2-4 leaf stage is much more effective than at the 5-6 leaf stage.
—Reduce harvest losses.