By Diana Dunlop, Regional Crops Specialist - Outlook
As seeding progresses, it is important to keep in mind that several insect pests could pose a threat to canola production in the Western Provinces. For instance, flea beetles overwinter as adults and are one of the first insects to move into an emerging canola field.
Keeping this in mind, it could be beneficial to use an insecticide/fungicide seed treatment combination. Late seeding can sometimes increase the risks of insect damage occurring in canola fields. Since seeding is occurring a little later this year, other practices can be used for protection against insect pests such as increasing the seeding rates or direct seeding into stubble.
The most important step for defense is to scout the fields throughout the season especially during the seedling stages. For example, the action threshold for flea beetles on canola is 25 per cent of cotyledon leaf area consumed. The traditional symptoms of flea beetle damage in canola include shot-hole feeding and girdling of young stems. The pinched-like symptom of young stems can occur during unfavorable temperatures (i.e. wind, cooler temperatures, precipitation) so it is essential to monitor for damage closer to the soil surface. If treated seed is not used or is not successful in protecting the field, a foliar-applied insecticide may be used.
It is also important to note that there are many other insects that can impact yield and health of canola plants later in the growing season. Some of these insects include the bertha armyworm, diamondback moth, cabbage seedpod weevil and wireworms.
Information on economic thresholds and different control methods for each pest can be found on the Saskatchewan Agriculture Ministry website at http://www.agriculture.gov.sk.ca/crops or in the 2014 Guide to Crop Protection.