Interesting thread.
Here (UK) it is illegal to use moth balls (para-dichlorobenzene) to prevent wax moths. Some worries about it potentially contaminating the wax in the comb and then leaching out into honey next year.
Greater Wax moth is our major problem. For years I used to spray my brood frames with Certan B401 and store in my bee shed. Then it became unavailable. I was told by supposedly reliable sources that dipel BF would do the same job. It?s made from a different bacteria than B401 and is used for biological control of garden caterpillars and other pests.
I can tell you it doesn?t work for wax moth, over here at least! I lost over 12 full boxes of drawn brood frames that winter. All sprayed as usual and stored in bee shed.
Currently now changed practise to treating frames with burning sulphur strips before sealing top and bottom of the stacks with poly sheets and storing them outside. I think the combination of the Sulphur dioxide from the burning strips killing any insects (or eggs) present and the relative cool temperatures outdoors stop any further infestation. The down side is I get quite a few mouldy frames next spring, particular any with pollen stores in.