It sounds like you were the victim of a moth attack. We see this kind of damage all the time and it almost always follows the following telltale pattern.
Moths are peculiar little insects that are notoriously shy and love to hide in the deep dark corners of your closet. Moths are desperately afraid of light and afraid of people. In fact, most people with moth damage have never actually seen a moth in their home let alone their closet.
There are some strange facts you need to know about moths. Firstly, it wasn’t actually the moth that made those holes in your sweater or suit—it was the moth’s newly hatched larvae. Secondly, moth larvae are not these crazy wool-eating beasts you probably think they are. In fact, no one is looking to eat your wool items at all, they are just attracted to an old food stain you probably weren’t even aware you had on your sweater from last season. Did you ever wonder if that little spot of milk you accidently spilled on your sweater left a stain? By the time is dries you cannot even see the stain…but to a moth it smells like a picnic.
With its incredible sense of smell, a moth seeks out that invisible food stain on your clothing and lays its eggs at that exact location. These eggs are so small you would likely never even notice them in your closet. The moth is smart enough to seek out the dark corner of your closet that never sees the light of day. It wants to give the eggs enough time to hatch without being disturbed. Moths love to lay their eggs on top of a food stain so that as soon as the larvae hatch it has some nourishment. Unfortunately, these blind larvae can digest wool (they cannot digest acrylic or synthetic fibers so that is why you only see the holes on your wool items). They aimlessly start eating the stain left in the wool and eat some wool in the process. What you are left with are these unsightly little holes. The good news is that once the larvae grow into moths they have no interest in your wool items—unless you leave them in your closet without cleaning them.
I know this is hard to believe but the single best way to NEVER have a moth problem is to clean all of your wool items before you put them away for the season. If you eliminate the food source, you eliminate the moth damage.
“NEW DOES NOT EQUAL CLEAN”
Keep in mind that just because a wool item is new does not mean it is clean. I know you do not want to think about this but how many people have already tried on that wool blazer before you bought it? Between manufacturing, packing, shipping, unloading, unpacking, pricing, tagging, displaying, moving, arranging, etc. literally hundreds of potentially dirty hands have touched that “new” item (and I am not even getting into returns).