Most of the winter canola I have looked at this fall has the presence of the Diamond Back Larvae. None to date have had a high enough population to warrant an insecticide alone, but I would add the insecticide to your glyphosate application. Once the canola leaves start drying down with colder temperatures if the worm starts chewing or damaging the bud, there might be some yield loss.
Most acres with canola have an unwanted plant of some type (cheat, rye, rye grass, jointed goat grass, etc.) associated with them. That is often why canola got planted there. Don’t lose the opportunity to take two shots at eliminating these unwanted plants by skipping a glyphosate application. Fall and winter/spring. Timing can get tricky waiting on moisture to sprout as much as possible while the canola plant continues to leaf out and cover the ground area, but glyphosate will find unwanted plants that often goes unnoticed by the eye. What few you miss with the first shot you should pick up with the second application later in the growing year.