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VIDEO – Check Your Cocoons for Mono Wasps

It’s the end of May and mason bee season is wrapping up. This is also the time for mono wasps to start to emerge. If you’re able to, please examine your cocoons and snip the tips off the cocoons that have not emerged. If you find mono wasp, please dispose.

Reader Interactions


  1. Brian Van Putten says

    I did not know about washing my cocoons’ and candling. Can this be done just before I set my hatching trays out? I am having issues with Sapyga invasion. Could this be slowed by candling?

    • Thyra McKelvie says

      Hi Brian,
      You may not have time to wash them this late in the season. Any change in temperature will cause them to start to emerge. For now, it’s best to open up all nesting material. Pull the viable cocoons out, brush them clean with a small brush. Then, you can candle them to see if any wasp invasions. Make sure you’re doing all of this outside, bringing them inside will warm them up.
      Then, the cocoons you “rescue”, place in a box (pudding, jello box) and poke a hole in the side they can emerge from when ready. You can’t place loose cocoons out or the birds will have a feast. Thank you!

    • Thyra McKelvie says

      It’s too late to wash them because temps will warm up and they’ll start to emerge, but you can remove the cocoons from the nesting material and dispose of any predators (pollen mites, chalkbrood or houdini fly larvae). Then, place the saved cocoons into an emergence box, like a pudding or jello box with a hole cut in it. Here’s a video on how to do that. Just skip the washing part.

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