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).
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.
Will you clean your mason bees and their house before December? Please share any tips or advice from your experience!
Lindsay Coulter, Queen of Green