Asked April 23, 2024, 4:52 PM EDT
This is my third season with mason bees. The first two seasons, I didn't harvest my cocoons and saw lots of mason bee activity in the Spring. This Fall/Winter was the first time I harvested, cleaned, and cold stored my cocoons. I put half my cocoons outside 3/17/24 and I put the rest outside 3/31/24. The bees were very slow to emerge. The majority of the cocoons were still unopened as of 4/18/24. No bees have emerged in the last 5 days and it has been reaching a high of 55-70+ each day. There hasn't been any scratching noises or movement in the cocoons either. I decided to cut open a few cocoons to see if they had mono wasp larva, but just found dead bees. I continued to open cocoons. Out of 65 cocoons I opened, only 3 had mono wasps. The rest were dead bees that didn't look to have anything wrong with them. I am trying to figure out what I did wrong. Why did over 80% of my bees die in their cocoons?
- Cleaning: I followed directions I found on OSU extension (1 tbsp bleach to 8 cups water), didn't leave cocoons for more than 2 minutes in bleach solution
- Storing: Fridge crisper drawer in small cardboard box with holes. Included damp paper towel. Even with the damp paper towel, the humidity was really low (I didn't realize until I bought a thermometer with humidity reader). So the bees were stored at only 30-40% humidity for a few weeks before I modified the crisper drawer to keep at 80%+ humidity. Could this be what killed them?
- Releasing: when no bees emerged after a couple days of putting out the cocoons, I opened the attic so the cocoons would get more warmth since the temps were 55-60ish until recently. Could direct sunlight be what killed them?
I am really trying to target how this happened so I can avoid in the future.
Multnomah County Oregon