Growers who seeded canola a couple weeks ago will want to start scouting now for emergence issues. Often if seed and seedlings are damaged by rots and blights, which tend to be a more common occurrence in cool soils, they will quickly dry up and disappear. You need to act fast to accurately diagnose the problem. Walk fields and look for missing patches.
In those patches, look for wilting or dead seedlings. Examine the roots and hypocotyls for signs of decay, and dig in the seed row to find the seeds. If ungerminated seeds are still firm and intact, it may have been too dry for them to sprout. But if the soil is moist and the seeds are squishy and rotten, they are diseased and unlikely to grow.