A reader in Maryland was told by a master beekeeper that 1) there are fewer chemicals in purchased foundation than previously thought and 2) foundationless hives have just as many chemicals as hives containing purchased foundation. She doubted these gems of wisdom and wanted to know if I’d seen any research supporting these claims.
First off, all the research I’ve read on this subject reports alarming amounts of pesticide—both number and quantity—in manufactured foundation. Particularly common are the acaricides fluvalinate and coumophos, which are used to treat colonies for Varroa mites. I’ve seen no papers claiming otherwise. Furthermore, it seems highly unlikely that foundationless comb would contain as much pesticide as comb built on commercial foundation.
Just think of it logically. Commercial foundation is made my companies that purchase wax from a variety of beekeepers. Usually it is large-scale beekeepers who sell their wax because most small-scale beekeepers do not have enough wax to bother selling.
For various reasons large-scale commercial beekeepers are more likely to use chemical pesticides such as fluvalinate and coumophos in the hive and they are more likely to have their bees working in agricultural areas where multiple pesticides are used on crops. So the wax coming from these hives is more likely to be contaminated with an array of acaricides, insecticides, herbicides, and fungicides, all of which go into the commercial foundation.
Now suppose you start two new colonies, one on commercial foundation and one foundationless. Even if both colonies bring in pesticide from the field—and even if you treat both colonies with acaricide—the one with the commercial foundation is going to have more total contamination than the other because it had a head start. It is just numbers.
So even if the amount of pesticide in commercial foundation is less than originally reported (which I doubt), there is still going to be more total contamination in a hive with commercial foundation than one without.
Isn’t it possible that your foundationless colony foraged in places with more pesticide than the other colony and ultimately became even more contaminated? Of course it’s possible. But is it likely? Absolutely not.