Pest observations

This is the tricky part of harvesting, and the primary reason you’re harvesting.

“What’s going on in your nesting material that is harming your mason bees?”

A couple of points on pest observation. 

• A few pests are fine (unless you find chalkbrood)
• A lot of pests should have you concerned.
• An old mason bee tube from a few seasons ago may have opened cocoons deep inside with new cocoons from this past season on the outside.
• For a complete breakdown of pests, review our section on pests.

If there is a pest in the straw, you should be able to poke around and see what it is.  Typical pests might be a carpet beetle larva (photo on right) or mono.

What can you do about this in the future? In general, nesting material left outdoors and unprotected past June are susceptible to pests. We’d like to help remind you to bring them inside next year! Sign up for Bee Mail.

I find “orange sawdust” between some of the mud partitions. What’s that?
This is pollen mites and its feces. The pollen mite is clear, and the orange coloring is feces. You probably live in a moist environment where pollen mites thrive.You can’t prevent the mites from hitchhiking on your mason bee with the pollen, but you can remove them from creating even more pollen mites in the spring. Read about solutions in pests.
In the spring, mason bees will need to crawl through these infected cells.  Mites attach themselves to the mason bee, which can prevent them from flying.  Mites drop off into the fresh pollen and breed even more pollen mites!

What can you do about this right now?

1. Consider the amount of pollen-mite-filled “pockets” that you’ve found so far and the number of unopened tubes in front of you.  You will lose a few mason bees in the spring if you don’t open all mite-filled tubes, leaving the bees to crawl through the mites.  You will also get a buildup of mites as they will be spread out through the tube.  Next season’s mason bee using that tube now has additional mites infesting other egg chambers.  Chances are that future hole will have no surviving larvae. 
2. It depends on how much effort you want to make to save the mason bees. If you have only a few mites, then consider leaving some tubes unopened.
3. There are means to rid your nesting material from pollen mites through a heated incubation program.  Crown Bees feels that this is over-the-top and not worth the effort.  Pollen mites are just part of nature and are best handled during harvest.