monodontomerus obscurus

Remove bees from the field to the storage shed, barn, etc., in late May. The bees (developing brood in tubes) are put in large cardboard boxes (or garbage cans, if mice are a problem) with only a slit left open for wasps to emerge through (the July brood). When in storage containers, tubes should be laid horizontally, as they were in the field. The boxes with bee tubes are then put on shelves in a dark storage shed that has only one window (facing south). Ordinary fly paper is hung inside the window to trap wasps, which come to the light from the window in July. Most wasps do not find their way back to the bee tubes in the dark boxes. They get stuck on the fly paper or die of starvation. By this simple, easy method, I have been able to maintain hornfaced bees for about 15 years with less than 1 percent parasitization. -- Dr. Suzanne Batra, Pollinator Paradise

That's 1-inch wide tape the wasp is stuck to.

After removing the mason bee house from the field, the bees need a few more weeks to develop before entering diapause. I like to use the solstice as a target date, but mono forced us to act a little early this year. The trays should stored where they are exposed to daytime highs and nighttime lows but are sheltered from direct sun or rain. This allows the bees to properly develop and spin their cocoons, which can be safely harvested in late August. Around Labor Day, I like to bring them indoors where temperatures are stable (the basement is nice and cool), to transition them to cooler temperatures before placing them in cold storage for the winter.