The moths eat wool and silk, putting historic artifacts—like a tapestry gifted to the house by Catherine the Great—at risk
from the article
"The tiny wasps provide pest control because they lay their eggs inside of common moth eggs. The wasp larvaeatsthe moth egg from the inside, and a wasp hatches. Over time, the Trust hopes that the parasitic wasps could wipe out the moth eggs and stop their population from growing.
The wasps need to catch the moth eggs early, or else after a few weeks, they’ll hatch into larvae that spend months munching on natural fibers. Eventually, the larvae build cocoons and grow into adult moths, whichcan’t eatand don’t cause any additional damage—except to lay more eggs and continue the cycle."