Carpet Beetles

As I am writing this article it is a few weeks before Christmas, perhaps a little late to just now be making a nasty discovery. Perhaps you already have pulled out the wool sweaters or scarves, or wool-lined gloves or slippers, in hopes of keeping yourself and your extremities warm in the winter months. Hopefully you did not cast your eyes fondly over these cozy articles of clothing and discover, to your horror, lots of little holes where little holes should not be.

If you did, however, the culprit just might be Carpet Beetles, one of nature's insidious little creatures that works its role in the darkness and quiet of our closets. Actually, if we try to think kindly of carpet beetles for just a moment - come on now, it's only for a moment - we realize the vital part these creatures play in the smooth operation of "The Environment". Why, without carpet beetles we'd have a lot of hair lying around on the ground, the remains of animals since passed away. For you see, carpet beetles are some of the very important "recyclers" in nature, and it is put upon them to eat and recycle the remains of dead animals, including dead insects. Since every animal will, eventually, cease to live, nature employs her crew of scavengers to turn all that solid material back into useful ingredients in the soil.

Just what is a Carpet Beetle?

In a way, this now is an unfortunate and misleading name to give these beetles. For many decades the carpets laid upon our floors were commonly made from wool, and thus were susceptible to feeding damage by carpet beetles. Since they were so commonly found damaging woolen carpets these beetles were given this common name. Now, of course, carpets are rarely made of wool, and the synthetic fibers that are in use today are of no interest to the hungry beetle. Sometimes you may still find the foam pad under the carpet being attacked, as some kinds of old waffle-pads still have wool threads in them, but most carpets today will not be attacked by these bugs.

Carpet beetles are in a family of beetles called Dermestidae, and professional pest control people often will refer to them simply as "dermestids". There is one group of dermestids that are more properly called the Hide Beetles, and they can be found feeding on the leathery skins and remaining tissues of an animal's carcass, long after it has dried out. Museum personnel even employ hide beetles to help them clean off the tissues from a skeleton that the museum would like to arrange and display, but in as pristine and aesthetic an appearance as possible. Should you find some of these hide beetles wandering in your home it is a good sign that there is a dead animal someplace - perhaps in the attic, the crawl space below, or even in the wall voids - that has been there for quite awhile. Remove the carcass and the beetles will leave too.

The beetles we more commonly think of when we speak of "carpet" beetles are some very small ones, most with sort of a checkerboard pattern of black, white, and orange colors on its back. This is the adult stage, and in a sense this is not the stage that you need to worry about, because the adults do not feed on wool fabrics. Instead, they feed on pollen and other plant tissues outside in the garden. However, since little carpet beetles only come from bigger carpet beetles, then the adult beetles are unwelcome in the home too.

The stage of the carpet beetle that does all the work in ruining your clothing or other woolen fabrics is the larva stage. This is kind of akin to the caterpillar eating your plants while the butterfly sips at nectar. We love our butterflies, but must recognize that their children may lead to plant problems. The carpet beetle larva is a small, hairy, brown critter that moves around pretty well. They wander actively and will be found on the walls or floors almost anywhere in the home, looking for potential food sources. We'll take a look at some of those possibilities in a few minutes, when we discuss how you can prevent them.

Is it clothes moths or carpet beetles - all I found was a hole!

There are such things as clothes moths, but these are pretty uncommon in the U.S. at this time. They DO occur, though, so it's certainly possible that you could have moth damage. One thing to note, though, is that clothes moths absolutely despise light - they hate it and they avoid it, both as larvae and as adults. So, if you find some moths flying around your reading lamp at night it definitely is NOT clothes moths. When the lights come on these guys hide.

As moth larvae feed they tend to leave a lot of silk webbing on the surface, and beetle larvae do not do this, so the absence of silk is one clue that it may be carpet beetles. The beetle larvae also leave a lot of powdery fecal matter on the surface, so look for that. As do all insects as they grow, carpet beetle larvae will shed their outer skin on a frequent basis, and the presence of these hairy little skins laying around is another clue as to the intruder. Finally, of course, look for the larvae themselves, by carefully inspecting the material, the storage box or bag it was in, or the area around where you stored things.

Where could I find carpet beetles in my home?

The old adage "Think Like a Bug" was never more important than it is when it comes to a seek-and-destroy mission for Carpet Beetles. Remember, that these recyclers feed on anything that originally was covering an animal's skin - hair or feathers - and therefore you must begin to think of all those possibilities around the home. Unfortunately, carpet beetles also feed on grain-based products, so it is very possible that they could be infesting many of the foods in your cupboards too. After picking 2 or 3 carpet beetle larvae off of my own kitchen counter every morning for a couple of weeks, I finally took a close look at boxes of food in the cupboards. What I found was a large box of corn bread mix that we had not used for years, and hundreds of larvae were in it.

Solution: throw it out.

Here are some of the many places carpet beetles may be found, in a structure, feeding on foods that can sustain them:

  • Behind the clothes dryer - the buildup of lint includes lots of wool
  • Under the fridge - spilled foods roll under there and get hidden
  • Window sills - accumulations of dead bugs in the window track
  • Wasp nests - paper wasps and mud dauber wasps leave lots of things behind in their nests once the adult wasps leave - look in attics especially
  • Dead animals - dead rats in the attic, dead birds that got into a wall, dead animals under the house in the crawl space area
  • Food packages - baking goods, meal, cereals, breads, noodles, or anything other foods made from grains
  • Wool - sweaters, slippers, gloves, carpets, blankets, the felt pads under lamps, felt pool table surfaces, felt hands on dolls
  • Feathers - animal mounts, feathers in flower or picture arrangements, feather accumulations from a pet bird, bird nests in the attic or under the eaves
  • Hair - stuffed animal mounts, brushes or brooms, coats, buildup of shed hairs from pets, possibly in cracks around the floor or under cushions on furniture
  • Seeds, nuts, grains - in bags of food in the kitchen, in dried flower arrangements, in Christmas wreaths, in decorative picture arrangements
  • Pet foods - boxes of dog biscuits, pet snacks, spilled foods
  • Rodent bait - bait packs or blocks thrown into the attic or crawl space

I think you can see, that this list could just go on and on. However, it should be very clear that these beetles are very, very adaptable to feeding on many different foods, and until you find and eliminate all of them you will still either have the beetles or be inviting them in. Try to evaluate those possibilities that currently are NOT infested, but are stored in such a way that they could BECOME infested, and change the storage. Clothing set aside from one winter to the next should be in sealed storage. Moth crystals will be a deterrent to the entry of carpet beetles, but also may impart an objectionable smell to the clothing. Cedar chests are somewhat repellent to clothes moths and carpet beetles, but please do not rely on them. We commonly find these pests ruining clothing stored in cedar chests, especially older chests where the wood has greatly diminished the odor it gives off.

Do NOT have any reliance on sound-emitting devices, no matter what the advertising says. They simply do nothing to repel insects.

Well, I found the problem, now what do I do?

Unless you have a high tolerance for living with or eating bugs, once you find infested materials it probably should be discarded. Of course, if this is clothing or furnishings or some other valuable item you can remove the bugs with vacuuming or dry cleaning, and then see if the damage can be repaired. If it is a food material that is infested just put the whole thing in a plastic bag and toss it in the trash. Even though you can kill the bugs with cooking or freezing, and they are, after all, "protein", it is not healthy to eat carpet beetle larvae or their shed outer skins. Some people have exhibited health problems after doing so.

Thorough cleaning of areas that have accumulations of carpet beetle food will remove both the food and the carpet beetles, and if you then can make some sort of "fix" to prevent it from accumulating a second time, that is good prevention. For example, I just changed and correctly (this time) installed the vent duct behind my own clothes dryer. The old one did not fit properly and a lot of the lint was building up behind the dryer. More frequent cleaning of window sills keeps out the dead flies. A crawl around the attic with gloves and a plastic bag will allow you to remove all the bird or wasp nests there. Just make sure the wasps are not active at the time - winter is best.

You also should give consideration to contacting a licensed pest management professional. These folks often have many years of experience in searching for the sources of carpet beetles, and can come up with ideas that may not occur to you or to me. Detective work really is in effect here. Beyond simple removal of the source and thorough cleaning and vacuuming of the surrounding area, there is some benefit to the use of a "residual" insecticide, and the licensed professionals have access to some excellent products that are not sold on retail shelves. Just because the public cannot buy them does not mean they are too dangerous for your use. On the contrary, most of the insecticide products used to control pests in homes today are much, much lower in hazard than materials just a few years ago, and they now have little to no smell to them. An application will help to intercept wandering carpet beetle larvae, and possibly also kill adult beetles that fly in from the outdoors to lay their eggs.

So, there we have it, and hopefully this is helpful. The best definition of a "pest" is - something where we don't want it to be - and I think this fits carpet beetles very well. Their role as Nature's Recyclers is a vital one, and all they are doing with your lovely wool sweater is attempting to recycle the hair in it. However, they don't realize that you really aren't quite through with it yet.