How to harvest mason bee cocoons | Queen of Green | David Suzuki Foundation
Photo: How to harvest mason bee cocoons

October to December is the best time to clean mason bee nests and harvest cocoons.(Credit: Lindsay Coulter)

If you follow my investment strategy to protect nature, you'll recall that I spent 20 dollars on 20 mason bees two years ago. This weekend, I harvested over 100 cocoons (according to Dr. Margriet Dogterom, that's about 45 females and 55 males) from my mason bee house — an excellent return!

How to clean a mason bee house

Keep parasite numbers low and prevent the spread of disease within the colony by cleaning your mason bee house (and the bees!) and discarding suspicious cocoons.

Cover your work area with newspaper to collect debris like mud and bee poop. Remove all plastic or wood trays from the house. Carefully pry cocoons off and set them aside—inside are fully developed bees in hibernation. Soak trays in soapy water, scrub them with a brush, and rinse thoroughly. Soak again in a five per cent eco-friendly oxygen bleach solution to kill bacteria and fungi. Rinse well and let dry.

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How to clean mason bee cocoons

Sort your straws. Look for holes in the tube or if the mud at the entrance has been compromised. Identify suspicious cocoons with this video from Crown Bees. Unravel the tubes to separate cocoons from mud (grey), pollen (yellow), mites (red/orange) and bee poop (brown/black).
Mason Bees 036.JPG

Place cocoons in a sieve and gently rinse with tepid water. Once the water becomes clear, place cocoons in a bowl or pail of five per cent oxygen bleach solution. (Don't worry! Cocoons are buoyant and water repellent.) Soak for 5-15 minutes, stir, and then scoop the cocoons up with the sieve and rinse them well to remove all traces of bleach. Do not use soap or detergents—that will kill your bees! Place washed bees on paper towel to dry for about an hour.

Identify "suspicious" cocoons

Non-parasitized mason bee cocoons will be firm to the touch and dark-grey in colour. Keep these. Cocoons that are lighter in colour and "crispy" to the touch are likely tiny parasitic wasps. One infested cocoon can contain up to 60 developing wasps!

Bee cocoon winter storage

Mason bee colonies can be wiped out by ants, woodpeckers, squirrels, racoons, and bears. They're more likely to survive the winter if you eliminate this risk. Add clean cocoons to a paper box full of tissue or paper towel. Place the box inside a plastic yogurt container, glass jar, or metal tin—whatever will keep mice and moisture out. Punch air holes in the lid. Store your container in the fridge at 0º to 5º Celsius, in an unheated garage, or outside. Mason Bees 040.JPG

Will you clean your mason bees and their house before December? Please share any tips or advice from your experience!

Sincerely,
Lindsay Coulter, Queen of Green

October 31, 2011
http://www.davidsuzuki.org/blogs/queen-of-green/2011/10/how-to-harvest-mason-bee-cocoons/

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5 Comments

Oct 04, 2014
8:38 PM

I harvested my first batch of cocoons today. I’m glad I did it in early October because if I waited longer I would have lost a lot more cocoons. 1/4 of my yield was destroyed by mites, wasps or some other parasite. Some did not fully develop either. I rinsed the cocoons in tepid water and let them dry for an hour. Then I put them in a container of moist sand and rolled them around and then rinsed them again. After going through all of my cocoons, I did not see any mites or poop. They are very clean. Hopefully I’ll have a good hatching in the spring. :)

Oct 14, 2013
2:46 PM

Our Mason bee house is just a block of wood with holes drilled in it It has no wooden, paper, or cardboard straws in it. The bees have used it and we don’t want to harm any bees or cocoons. But. we would like to give them a clean house. Some holes look full and some empty so can you tell us what to do, please? Thanks

Oct 10, 2013
4:23 PM

Also..Crown Bees is doing a Share Your Bees campaign. If you have more than enough for your fruit trees and yard, we’d appreciate it if you send us your extra bees :)

See links for more info: http://crownbees.com/shareyourbees/ and http://crownbees.com/how-many-mason-bees-are-needed-to-pollinate-a-tree/

Oct 10, 2013
4:00 PM

Woo Hoo! Nice post :) And thanks for linking Crown Bees in the post :)

-Hien, communications manager/social media teammate for Crown Bees

Nov 13, 2011
10:31 AM

Great article. My only criticism is the use of bleach. Bleach is kind of harsh and unforgiving. Personally I think the foundation of sustainability is respect for all living things. Why use bleach? To kill bacteria, viral diseases, and fungal organisms. The proper handling, cleaning, drying and storage of the cocoons is enough to knock back many of the diseases and disorders that affect mason bees. Leaving a toe hold for even the meanest of creatures ensures that the bees are able to express resistance and develop genetic and behavioral responses to these pressures. A little disease goes a long way to ensure healthy bee populations!

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