Wax moths can destroy a lot of comb in a short amount of time. I never take them off the hives until the first hard freeze. That way the bees can protect them from the moths and the moths that are flying around laying eggs have died from the cold and its very likely that a hard freeze will happen again soon and kill all the eggs in the combs.
If you want protection without moth balls, and without waiting for a hard freeze or if you don't have that kind of weather, use Certan or Bt. You can buy the kind specifically for wax moths from www.beeworks.com
or you can go to the garden store and buy the ones they have there for cabbage worms or whatever.
You spray the comb with the Certan and it will kill any larvae before they do any damage.
Here's where you get it:http://www.beeworks.com/usacatalog/items/item134.htm
Here's info about it:http://maarec.cas.psu.edu/PDFs/Wax_Moth_pm.pdf#search='wax%20moths%20certan