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Unexplained Breaking or Exploding Bow Hair

Perhaps you are cleaning out your basement and unearthed your childhood violin or are returning from vacation and opened your viola case to play and discovered an explosion of bow hair. If the bow seems otherwise intact and there seems to be no cause for this random phenomenon, you may be the victim of (what we in the string industry call) bow bugs.

Bow bugs are dermestid beetles (more commonly known as “carpet beetles” or “skin beetles”) and are frequently not even noticed in a home until they crawl into a cello case and feast upon bow hair or climb into a clarinet case and feast upon the instrument’s pads. We will refrain from posting pictures of the actual bugs for those of you who may find bug pictures a reason throw your cellphone, but below you can see a picture of a single bow hair that has been eaten by a bow bug.

A magnified view of the horsehair on a bow. A single hair sticks out which has small, uneven bite marks along its surface.

Bow bugs are especially destructive in their larval stage and that is when they typically get into cases. You may see signs of bow bugs in your case beyond a number of broken bow hairs—you may see either the bow bugs themselves which look like a 1-2 mm long, red-brown meal-worm, or they may have already vacated your case and simply left behind their little shells.


What Do You Do If You Suspect Your Case Has These Unwelcome Tenants?

The first thing we recommend you do is remove your bow(s) from the case and bring it in to have it rehaired. Next, we recommend you remove everything else from your case and thoroughly vacuum the case, making sure to carefully get into small spaces like pockets and where the head of the bow is normally stored. After vacuuming your case, there are two commonly recommended case treatments:

• Treat the case with a pest repellent safe for cloth (always test these in an inconspicuous place in the case before spraying the whole case and read instructions carefully) and place them in the sun for an hour to dry. (Some of our customers have had success with Permanone. **If you have cats in your home, we do not recommend using Permanone because it is very toxic to cats.)


• Our preferred method: Place a small cedar satchel (like those used for closets) in the case to deter the bugs from re-entering the case. You can typically find these in home goods stores or online. (We typically do not recommend mothballs because of their overwhelming odor and the difficulty required in cleaning their residue off of instruments and bows.)


How Do You Prevent Bow Bugs from Returning to Your Case?

Our best advice is to practice daily! Bow bugs are less likely to appear in a case that is frequently jostled by opening and closing and removing items.

If you are unable to practice weekly or will have to leave your bow unattended for an extended period of time and are concerned a cedar satchel may not be enough to protect your bow, store your bow in a plastic sleeve so the bugs aren’t able to get to the bow hairs.

If you have more questions or need to get your bow inspected or rehaired, don’t hesitate to call, stop by, or e-mail us! To see our pricing on rehairs, check out our Repair Page!

Posted on: 26th April 2016
Updated: 8th September 2023