This page is credited in full to Dave Cushman who created it. His voice is expressed in black colour text and any additions or comments in blue belong to myself. Credit: Dave Cushman’s website.
Treatment Against Waxmoth
and general sterilisation of honey comb
Total control is unlikely to be achieved, the strength and health of the bees themselves is the best starting point. It is quite normal to find an occasional adult waxmoth or a few larvae in an active hive.
Hives that have weak colonies, or too many combs for the amount of bees to cover are ideal places for wax moths to get a stronger foothold, in which case the quantity of adults and larvae found will increase, along with the evidence of damage.
Good beekeeping practice including scraping of burr comb and propolis from hive and frame woodwork will reduce the opportunity for wax moths of either species to become established.
Combs in storage are ideal breeding grounds for waxmoths. Drawn comb is a magnet for eggs to be laid in or on or just close to. Warm storage temperatures also accelerate the destruction process. If you intend to store comb out of the hive, you must protect it in some way.
‘Wet’ storage of extracted comb has some merit from a moth control/avoidance point of view, instead of returning extracted supers to the bees for cleaning up, they are left with the small residue of honey that exists after extraction. I have personally done this successfully, but it causes a second set of problems in that any crystalised honey already in the comb when they are used again next season will seed early crystallisation of the subsequent crop. Furthermore any cells around the fringes of the comb that contained honey that was not fully evaporated may have fermentation occur in the residue, which can cause dysentery when the combs are returned to the bees.
Irradiation with gamma rays will kill all developmental stages including eggs, but costs are high and you still have to find a suitable storage container, that is totally moth proof, to house the combs after they have been sterilised.
Various fumigation methods can be used, but care must be taken that no remnants of fumigant are left impregnated in the wax. And of course adequate precautions must be taken to avoid inhalation of the fumes by human operators.
Acetic acid fumes have an effect and the method of use is the same as for pdb crystals, but the saucer is filled with 80% acetic acid instead of crystals. The acid is very corrosive and will attack metal fittings and fasteners. This kills the egg stage as well as all others and is useful to sterilise against Nosema spores.
Sulphur dioxide SO2 has been used, methyl bromide fumigation is offered by contractors, but it requires comb storage rooms that are completely moth tight. I believe this method gives protection against many diseases of bees as well as wax moth infestation.
Carbon Dioxide (CO2) can be used to exclude air, from comb honey that is intended for sale as well as for storing drawn comb in sealed containers or comb cupboards.
Heat… This needs close temperature regulation ( -0