You can order 'the good stuff' at
http://domyown.com/pests from these people and take care of any/all bug problem you may ever encounter .... and save a bundle by doing it yourself.
I'd recommend 'Advion WDG Insecticide' .... works well on just about everything. And it comes in pre-measured packets to make 1 gallon at a time. It's never let me down; although I don't have any experience with ground dwelling bees.