I was made aware recently, about a Florida beekeeping newsletter
recommending not to use coumaphos and TM together as it was causing a bad
reaction. If you look up coumaphos in the chemical book, Agricultural
Chemicals, it has  precautions on mixing with fluvalinate and I quote: "Do
not mix with other insecticides nor use in conjunction with oral drenches or
other internal medicines. Toxic to birds and fish."

The TM beekeepers use is an internal medicine and therefore in no way should
be mixed with coumaphos and could easily explain the problems beekeepers are
starting to have in Florida mixing the two.  Is this information printed on
the label?  I don't know since I won't use coumaphos.

-Barry