Nasty bow-hair-eating dermestids can be eliminated.

What They Are...

They are small, they're voracious, and they'd like to live inside your instrument case. Entomologists call them dermestids, members of the Dermestidae family of beetles. Different members of the family prefer different forms of protein: hair, cellulose, wool, even hide glue (their name, which derives from the Greek, means "skin eater"). Museum curators call them museum beetles (Anthrenus museorum) and stringed-instrument players know them as bow bugs. By any name, they're an undesirable presence.

What They Do...

It's possible that you've already met them. Bow bugs are largely responsible for munching bow hair, so if you've pulled an old, little-used bow from a case in the attic and found that its hairs are loose or randomly broken, you can guess that the bugs have been active. Richard Ward, of Ifshin violins in Berkeley, California, says he sees evidence of bow bugs almost every day in the shop. "The minute the customer comes in the door and you spot the dusty old case, you know you're going to see all this loose hair inside," he says. "You oftentimes actually see the hair sticking out of the case. Then you can assume that it's not their violin—it was Grandma's, say—or that they haven't played it in 20 years."

In addition to becoming suspicious of a bow with loose or broken hairs, you can sometimes actually see the tiny bugs—or at least their casings. The sheddings are hardest to spot as larvae, when they're about an eighth of an inch long and often brownish and mottled, which helps them stay camouflaged. As they mature, however, they shed articulated exoskeletons that can be seen inside a case. "They look like armadillo backs," explains maker Joseph Grubaugh of Petaluma, California. "They're a millimeter and a half long, roughly, and kind of a dusky reddish brown color."

"Occasionally people will come in and complain about a bow rehair someone recently has done for them, because the strings are already loose. And often we have to say, 'It isn't the rehair; you've got bow bugs.' You can see the evidence of them in all the crevices of the case."

However, Grubaugh adds that such situations are rare, because active players don't usually run into these creatures. The insects don't like light and prefer to make their homes in cases that have been stored, never opened, for long periods of time. Sometimes players are embarrassed when they find evidence of a bow bug infestation in an old case, but the problem is not unusual under such circumstances. Bow bugs are, unfortunately, likely to be hiding even in the cleanest of houses.

"They're all around us," says Gina Laurin, objects conservator at the Denver Museum of Natural History. "They live in carpets, in insulation, in closets, under the bed where there are dust bunnies. It's the larval stage that does the most damage, and they'll eat whatever is available to them."

In fact, many natural history museums like the one in Denver keep thousands of dermestids in huge cases for the express purpose of cleaning specimens. "Say you want to get a zebra carcass down to the bone—they'll eat that in a week or so," Laurin says. To protect precious exhibits, museum curators must keep a careful eye on these dermestariums to prevent beetle breakouts.

What You Can Do...

Luckily the insects don't infest ordinary homes in such quantity, although it doesn't take many to do damage to your bow. If bow bugs do get inside your case, you can get rid of them by following a few simple but important steps, according to violin dealers. First, remove the instrument and bow and check them carefully for any trace of the creatures. (Shops that take in old bows for resale will certainly throw away, and sometimes even burn, the hair from bows that show signs of bugs.) Next, if you plan to use and not store the bow, have it rehaired. While the case is empty, vacuum it thoroughly, using a narrow crevice nozzle to get into every nook and cranny. Then leave the case open in strong (though not direct) sunlight for a few days. In most cases, these actions are enough to wipe out the problem, although some people battling severe infestations have been known to try pesticides, such as powders or insect strips. And there is, of course, another way to make sure a case is clean: get a new one. Many players who have salvaged a long-neglected instrument and bow want to buy a better case to store them in anyway.

"But if the instrument is going to go back into storage, we tell people to clean [the case] out and not to even bother to rehair the bow," says Steve May, also of Ifshin Violins. "Then it's less likely the bugs will go back in there, because there's nothing there for them.

"Every once in a while we have someone who's in between—a fairly active player who knows that he or she won't be using the bow for a while. Then we tell them: if you have a safe place for that bow, other than the case, put it there. Such as out on a shelf—not in sunlight, but in a safe place while you're on vacation for a month. Then there's less temptation for the bugs to get into the case."

Bugs that eat bow hair are certainly a nuisance, but fortunately they are little more that that. However, Grubaugh and his partner, Sigurn Seifert, have also seen grips and frogs that have been severely damaged by dermestids. "If they go for a whalebone grip, you can think of it as a devaluation," Grubaugh says. "But it's mainly a historic loss: whalebone is irreplaceable and you can't legally buy it anymore. English bows, such as the old Hill bows, are what you usually associate with whalebone grips.

"But the winding is not like the frog. If the [bugs] go for tortoiseshell, they can severely diminish a bow's value instantly. A tortoiseshell bow is usually the most expensive bow of any of them: the most expensive Tourte bow, for example, is a tortoiseshell Tourte. And the tortoiseshell is fragile anyway and will succumb to wear—but it will succumb instantly to [bow bugs]. The frog would be devastating to lose."

Fortunately this scenario is quite rare, since most owners of bows with fine frogs do not store them in unopened cases for long periods of time—they use them. But no matter how often you play, and no matter what the condition and value of your bow, it is wise to know the conditions under which dermestides flourish and to take reasonable steps to guard against them. There's no point in letting any of your musical equipment become a free lunch for bugs.

Recommendations From Johnson String's Bow Technician Daniel Medina

Occasionally we're asked if there is a long-term preventative solution to bow bugs. There are a few things that can be done which help reduce the chance of them returning if a case must remain in storage for any duration of time.

The first option is a pest repellent designed for cloth. Two brands are "Sawyer's Permethrin" or "Repel Permanone" which bond to cloth. These can be found at an outdoor sports goods store or online. Odorless and relatively permanent, it is the our treatment of choice. To apply it, first remove everything from the case, including the instrument, bows, and anything in the accessories pockets, spray the interior of the case according to the directions, including accessories pockets and inside the bow holders, and allow to dry as directed. After it has dried, you may place everything back in the case.

The second option is using a bug-repelling botanical like cedar essential oil. Cedar oil may be found at storage supply stores. It is a little less reliable than the before-mentioned spray and will need to be reapplied periodically. It has a residual odor, which you may or may not find offensive. To apply cedar oil, remove everything from the case, spray once near where the scroll will sit in the case, and once by the chinrest end. Only use two spritzes. Allow the case to dry in roughly 1-2 hours and then you may place everything back in the case.

Some may suggest placing mothballs in the case. We do not recommend it. Mothballs leave a film of poison on all the surfaces of anything in the case, including the violin and the bow. It is very difficult to clean off and has a very unappealing odor. The chemical used to make mothballs is a neurotoxin and can cause long-term damage to your health. It is not something you want to place near your face as you practice for hours. See: wikipedia.org/wiki/Mothball

For more information about having your case treated at JSI, please contact Daniel Medina in the JSI Workshop: daniel@carriagehouseviolins.com