Amitraz Strips.

After eight weeks, it was time to remove the Amitraz strips from the bee hives; they’re made of plastic and impregnated with a chemical that kills varroa mites. The bees do not seem to be bothered by the treatment as the brown stuff is wax from where the bees were incorporating it into the structure of their honey comb. Needless to say, I only handle the stuff while wearing rubber gloves and it has now been wrapped in a plastic bag and deposited in the dust bin; I don’t suffer from varroa and so don’t see any reason to treat myself for it.
 
The mites live in the brood cells but are evicted at the end of each three week long brood cycle; since the wax cells are impermeable to the chemical, it is only effective while the mites are out in the open and the eight weeks treatment time guarantees that there are two chances of killing each of the buggers. Don’t leave the strips in the hive long enough and you lose the insurance of that second chance, leave it on too long and you’re encouraging the mites to evolve immunity. The “flat Earthers” who believe in “intelligent design” rather than evolution used to leave the medication in until the spring believing that the bees suffered if the hive was opened during the winter rather than believing the instructions on the medication. In practice, there are researchers who open hives every day of the year; it might not do the individual colonies any good, but they probably survive the winter better than those of most amateur beekeepers.