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The Ounce: Do The Flight Thing—How to combat webbing clothes moths in collections!

Welcome to The Ounce, an occasional missive for Harvard Library colleagues from Preventive Programs in HL Preservation Services.  

Many staff members inquire about pests or bugs they are seeing and if they are harmful to collections. Here at The Ounce, we have decided to send you an intimate portrait of one bug at a time throughout the year. 

In this issue we are focusing on the webbing clothes moth. 

A common clothes moth. 

Main image: the adult common clothes moth (© Olaf Leillinger, CC BY-SA 2.5, via Wikimedia Commons). Inset, the larval form on felt. (© Malcolm Storey, CC BY-NC-SA 4.0, via BioImages) 

Who am I? 

I am the Tineola bisselliella, also called the webbing clothes moth because my larvae make webs as they grow and eat. 

What do I look like? 

  • I’m less than ½ an inch long—8-10 mm. 
  • I’m shiny with gold scales. 
  • My larvae are hard to find. If you see them, they are white with a rust-colored head. 

What do I eat? 

I LOVE fabrics with protein, and I’ve evolved to live around humans because I like your sweaters, coats, and other clothing. When I arrive at a library, textiles, cloth bindings, as well as parchment and leather bindings can be tasty snacks for my larvae. Just look at what the folks at the Peabody have to say about the damage I can do and how difficult it can be to get rid of me. 

Part of a moth infestation discovered in June of 2016 in the largest ethnographic artifact storage room in the historic museum building.   

Part of a moth infestation discovered in June of 2016 in the largest ethnographic artifact storage room in the historic museum building. 

Image courtesy of https://peabody.harvard.edu/blog/moth-mitigation 

What should you do if you see me? 

  • Limit the amount of personal clothing kept in the library 
  • Take clothes home at night or store personal clothing kept onsite overnight in a snap-tight bin 
  • Contact preservation and/or facilities manager 
  • Coordinate with a pest service 
  • Advocate for non-chemical interventions that are safe for people and collections like pheromone traps which break my breeding cycle 
  • Do not attempt to apply pesticides yourself. 
    • Pesticides are regulated by federal and state law, and their use on campus is further restricted by EH&S. These products can and do offer value in some places, but only rarely within an occupied building. Note that only state-licensed pest control applicators are authorized to deploy pesticides of any kind at Harvard. Faculty, staff and students are prohibited from storing or using any pesticide on campus unless it is part of a research program authorized by the administration. 

Want a deeper dive? 

See also: Prevention