Wasp in tubes of the Mason bee house

Asked March 19, 2020, 6:21 PM EDT

I just emptied about 20 tubes with huge wasps inside. They appeared new and sluggish as if having hatched or overwintered there. Some tubes had as many as 5 wasps inside. The tubes were not sealed so it was easy to see which were wasps. I did leave it out all winter and I thought they were all sealed. What can I do to prevent this from happening again.?

Yamhill County Oregon

1 Response

This lovely spring weather has us all doing spring yard work. We are seeing yellowjacket wasps queens emerge from their wintering places. In late summer/early fall yellowjacket wasps queens find a sheltered spot to overwinter. It sounds like they thought the mason bee nesting tubes were perfect. To prevent this from happening this year, remove the tubes to a protected storage place after the mason bees have nested in them in June. That will foil those wily yellowjacket queens from even finding them.

The OSU publication, “Nurturing Mason Bees in Your Backyard in Western Oregon” has full details on the timing of nesting tube placement and removal, plus information about cleaning the cocoons in autumn. Enjoy the spring.