George Imirie's response to Kate's original post is absolutely correct.
Moths cannot destroy a colony, they can only finish off what disease,
mites or queenlessness has started.  I would only add to his response
that moth larvae also love to feed on stored pollen as well as bee
larval cocoons.  If I have a few cells of pollen in one of my clean and
dry stored supers, moths will often (but not always) find them.
 
Ted Fischer
Dexter, Michigan USA