Bob Harrison wrote:
''I respect Roger's opinion but our researchers say coumaphos stays in wax much longer than the five years Roger stated''

Bob, actually I said a minimum of five years - I do not know the upper limit and do not have acess to a laboratory where I could make measurements and calculate residues.  I suppose that environmental factors play a big role and as these are variable, the upper limit will also vary between colonies and locations.  
The effect of pyrethroids on drone quality is well documented.  There was a mention that the decline in drone quality was happening before the use of chemicals to control varroa.  A possible cause of this could be the chemical residues present in wax used to make foundation.  Even wax from Africa, which one would expect to be chemical free and it is often touted as such, has chemical residues in it.  The chemical companies, even though they know that many chemicals are harmful to the environment, continue to sell products that were banned years ago in most developed countries.  A chemical test of ''pure'' African beeswax from a fairly remote area, like Handeni in Tanzania for example, will reveal all sorts of chemical residues including chemicals such as DDT.  The amount present is very small, but may be enough to cause problems to drones.  Until recently PDB and napthalene were used in Europe as wax moth controls, I think that they are still used in the USA, at least they are still being advertised in the the US beekeeping catalogues.  These two chemicals were used for years and a large percentage of the combs are contaminated.
Best regards
Roger White
Superbee Cyprus.

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