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FROM LESLIE: I’ve followed the steps to clean the cocoons as outlined in your book. The cocoons were really heavily covered in mites, and there were many parasitic wasps present on and within several cocoons, which had holes in them (and which I discarded).
My question is how to clean the remaining mites off cocoons. The remaining cocoons are still not as clean looking and shiny as the ones I typically buy from Wild Birds in the spring. There’s some webby material still present on the outside, and what looks like possible clumps of mites. Should I rewash the cocoons and put them in the bleach solution again?
REPLY: Yes, do wash them again under running cold tap water. Use a metal sieve that will scour mites off the outside of the cocoons. use a bleach as the final wash to make sure that there are no fungi on the cocoons. Dr Margriet
Frank mentioned removing mites with a ‘large stainless steel colander’. The best colander is not just any colander. More about this later, but first, lets back up a little and I will explain my rationale for removing mites.
Getting rid or removing ALL mites from cocoons is difficult. I think the main aim is to remove the majority of mites, so that mason bees have a better chance of producing healthy offspring. Even if all mites are removed from harvested cocoons, there will be the occasional mite covered wild bee that arrives from within the local wood. These mites are spread successfully ensuring mites are always around. The best that anyone can do is to remove the majority of mites from harvested cocoons. This give mason bees a better chance in producing healthy offspring rather then mites.
Washing with water, removes adhering frass and the majority of loose mites. After washing, there are still lots of mites in amongst the threads of the cocoon.
These mites are best removed by friction. I have found the most successful way to remove these mites is to gently roll them over a METAL window screen stapled to a frame. Another way is to gently roll them around colander with a metal screen (NOT PLASTIC, NOT STAINLESS). Plastic and stainless steel do not have the abrasive quality of metal screen.
This can be done in two stages. First wash with the appropriate colander under and in running water. Second, when cocoons are dry, roll them over another screen to get the remaining mites off.
Washing with water, removes all frass and most mites. The removal of frass is an important part of the cleaning process because it allows cocoons to be candled. Successful candling can only be done with clean cocoons. I want to make sure that cocoons parasitized with little wasps don’t end up in the cocoons that I sell or place out for production.
Mites are pests for mason bees. Bees carry them from their old nest to their new nests, and then mites compete for food with the young developing bees. Mostly, if mites get into a cell with a developing bee and its pollen lump, mites will be the end result- not a bee.
Because mites on the surface of cocoons are waiting to be transported to a new nest by the emerging bee, it is imperative to get rid of most, if not all surface mites. Washing will remove the majority or mites. Rolling cocoons over a metal screen will remove the majority of the remaining mites.
Further reading on mite control ______________
A great DVD on How to _________________
Here are a few pictures of
Mites are transported by bees from the old nest to the new.