I put naphthalene balls whenever I put the winter clothes away . This way they don't have holes.When I take them out for winters,i first put them in sun to take away the naphthalene smell.. try this the next time.
thanks for the help guys..but i don't know what caused this and what should I do with these woolens..they were almost new and expensive. Cannot discard them totally
Silver fish is the insect which eats away the woollens.You can put dried been.leaves and naphthalene balls but make sure u wrap these balls in old soft cloth because sometimes the bad quality naphlene balls can stain the clothes .