Sort:  

Mason bees have a variety of pest and diseases mainly parasitic wasps, small mites, and chalk brood fungus. Harvesting the cocoons interrupts and breaks the disease/pest life cycle. You can use simple holes drilled into wood but after 2 or 3 years your population will crash. Some people use paper or cardboard tubes to line the hole so the bees can be managed and cared for.

Thanks! Very interesting. I guess I'm going to have to read up on them more and decide if I want to build a home for them here on my homestead.