Bay Leaves!
Honest! I had some weevils in my flour a couple of years ago, adn they were crawling around the cupboard, so I had a google and putting bay leaves in with the flour was mentioned.
Well, after washing out the cupboards, and tupperware that had the flour in, I now put a bay leaf or 2 in with the flour, a couple in the tupperware, and spread a couple around the cupboard, I haven't had one weevil since!