Mike,
 
>I wonder if anyone has any ideas on prevention
Prevention consists of maintaining a STRONG and healthy
colony.  Wax moths are not known to invade and take over
a strong colony (the bees eject them from the hive).
 
>eradication of wax moths?
I'm not familiar with any "in hive" treatment while live bees
are in the hive.  As mentioned above, if a colony is healthy
and strong, wax moths are not successful invading a colony.
Wax moths can only capture and take over a colony that is in
some kind of weakened or stressed condition.  Since all eight
of your hives (last year) were taken over by wax moths and you
know it wasn't varroa; we would need more details and/or obser-
vations as to the condition of your hives to try and detect what
might have caused this situtation. Again, the hives were stressed
or otherwise in some kind of weakened state and there are many
reasons why this might have occurred.
 
Storeage of hive bodies and frames is another matter.  Keeping
wax moths out of stored equipment is an easily accomplished task.
Regards,
BusyKnight
Dallas, TX