Managing moths at a museum


September 22, 2017

Custom Pest Solutions helps solve a Tineola bisselliella infestation at the Betsy Ross House.

While performing a residential termite inspection for a recently renovated farmhouse, I learned that the owner, Carol Spacht, is an actor with Historic Philadelphia Inc. She portrays Betsy Ross at the Betsy Ross House in Philadelphia. Ross is credited with making the first American flag as we know it, with stars and stripes.

During casual conversation, Spacht mentioned that the Betsy Ross House was experiencing a webbing clothes moth issue in the building and around the historical artifacts, and that my services could be beneficial to them. I thought this would be an interesting project for my company, Custom Pest Solutions, so I offered her my card and brochure to take to the museum.

It wasn’t until a year later that I received a call from Kim Staub, artifacts collections manager for the Betsy Ross House. I scheduled an appointment for an inspection and evaluation of their situation. During my inspection, I was informed that Staub and the museum’s director, Lisa Acker Moulder, were privately handling the moth issue up to this point. Their control measures were limited to the freezing of moth-infested items, inspecting the infested artifacts under magnification and physically removing clusters of moth eggs found by picking them off fabric and upholstery by hand. Staub told me that while this process helped greatly in reducing the population of moths, the low-level, lingering issue was problematic.

Handling with care

To create an effective program, I knew I needed to understand how long visitors and actors occupied the building on any given day so a safe approach for treatment of the webbing clothes moths could be developed. Staub had expressed concern that whatever approach was taken, it could not affect the integrity of the artifacts and must be safe for employees and guests.

I consulted with Pest Management Professional’s Q&A columnist, Dr. Doug Mampe of DM Associates, whom we keep on an annual retainer, about this project. We decided that the use of an insect growth regulator (IGR) in conjunction with a webbing clothes moth monitoring program was the best option. As a biorational insecticide, the IGR inhibits reproduction and adult emergence. It would be a low-risk, logical and cost-effective approach, and would establish a baseline of infestation. I was particularly confident in this strategy because my company had recently used it in a high-end condominium building in Rittenhouse Square in Philadelphia, and was able to gain control of its moth activity within weeks.

I submitted labels and safety data sheets (SDSs), as well as an outline of how the treatment would be implemented, to Staub and Moulder for approval. They quickly gave us the green light, and I reached out to the appropriate manufacturers of both the IGR and the webbing clothes moth monitor, both of whom generously donated product. Similarly, Custom Pest Solutions is donating the pest management services on an every-other-month basis.

Our first follow-up visit showed activity in the archives storage room, which we suspect may have led to the building-wide issue. Another area of concern was the Betsy Ross upholstery shop, located in the home, as she was originally an upholsterer.

Once our first follow-up revealed areas of activity, additional IGR and moth monitors were placed out to help narrow down areas of concern. Light activity was noted in various areas of the home, but it was clear that items stored in the upholstery shop and in the storage room were the initial sources of infestation.

The data from the monitors continues to be documented and looked at statistically. So far, there has been a significant reduction in activity, and the museum staff is pleased with the results.

Tom Silvestrini is president of Custom Pest Solutions, based in Blue Bell, Pa. He can be reached at

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Tom Silvestrini is president of Custom Pest Solutions, based in Blue Bell, Pa. He can be reached at

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