Invasion of the Miller Moths

Those of us in Sheridan have found 2002 to be The Year of the Miller! Thousands of the large gray moths – technically Euxoa auxiliaris or army cutworm moths – have made their presence known in recent weeks, setting off security alarms, dirtying up windows, and sneaking into every crack and crevice in the mansion. Therefore, the staff at Trail End battles bugs on a daily basis, vacuuming and sweeping them out of the historic house with great vigor.

In addition to millers, Trail End is regularly plagued by such bothersome pests as the persistent housefly and that ubiquitous Wyoming favorite, the Boxelder bug. While the moths and other bugs don’t do much damage themselves, they do tend to serve as food for other, more annoying pests. They’re also unattractive, both alive and dead. Management of such pest problems, while not the most exciting topic, is an important aspect of museum work, especially in a historic building that has the same gaps and crevices as any older structure.

While many people, including those who care for museums, have often turned to chemicals as the solution to an insect infestation, modern museum practices shy away from the use of chemicals in favor of less drastic measures. Chemicals are indeed effective killers of many pests, but according to Sherry Butcher-Younghans and Gretchen E. Anderson, it is now known that many of these chemicals are unsafe for humans and can seriously damage artifacts.* As institutions that invite the public inside to view exhibits, serve as the daily work environment for staff members, and strive to preserve artifacts for the long-term, museums are turning to more benign methods of pest management.

The first and best line of defense against any pest is prevention. Regular and meticulous housekeeping can often stave off an infestation. Insects thrive on dust, lint, and food particles, using them as both food sources and places to hide, so cleaning frequently and isolating food consumption activities to areas away from collections is always a good idea. In addition, any windows that are opened for ventilation should have tight-fitting screens.

Staff must always be on the lookout for signs of insect activity to prevent an infestation from spreading throughout storage or exhibit areas. Museums that discover a larger infestation can turn to some more advanced techniques, including freezing stable artifacts to eliminate bugs, using a vacuum or controlled atmosphere, and utilizing isolated chemical applications (rather than full-scale fumigation). All three techniques require special training, and are often undertaken only with the advice and expertise of a conservator.

Luckily for those of us enduring the millers this summer, the creatures are simply passing through on their annual migration and will soon diminish and disappear for another year. Meanwhile, we at Trail End will clean up the last vestiges of their presence and continue our quest to stay one step ahead of the various insect pests that may come our way.