Canola plants have been going through a lot of stress, and could be showing multiple symptoms. Good sleuthing means leaving the truck seat, putting on your booties and walking the fields. Getting to the bottom of any mystery takes keen observation (got your magnifying glass?), an open mind (the most obvious answer is not always the right answer) and a touch of skepticism (not everything can be cured with a splash of this and that).
Here are some tools to get you geared up for problem solving: