Collections Care: Pest Monitoring From the Professional Standards

Is pest monitoring in a campus museum, library, or archive set by regulation?

No regulation quoted on this reference sets it. Collections care is governed by professional standards. The practices on this page come from three bodies of guidance: the National Park Service's Museum Handbook and Conserve O Grams, the Northeast Document Conservation Center's preservation leaflets, and the MuseumPests Working Group at museumpests.net. None of them is a regulation.

The building is a separate question. Utah's general sanitation rule for public places, R392-800, says a public place may include libraries and museums. Which university buildings are public places under that rule is listed as an open question. See Utah R392-800.

Requirements attached to a particular collection, such as the terms of a loan, are outside this page.

Where should sticky traps go in collection storage?

Along the walls, at entry points, in dark corners, and on windowsills. The current NPS sticky-trap guidance lists:

NPS Conserve O Gram 3/7, Setting the Traps:

“Abutting the wall/floor junctions at intervals of 5-10 m (16-33 ft), depending on the room size. Traps should be flush against the wall to ensure passersby will encounter the sticky surface.

In corners, near doors, vents, fireplaces, or any potential entry point for insects.

In dark, hidden areas that are difficult to see and not often disturbed.

On windowsills, flush against the window or adjoining wall (if in an alcove).”

MuseumPests.net, Monitoring, Monitor Trap Placement:

“Invertebrates tend to walk along edges, such as walls of rooms so placing the traps along these paths will provide more accurate data.”

Give each location a unique ID and use the same spots each month, so catches can be compared over time.

How many traps does a collection storage room need?

As many as staff can check on schedule. NPS ties the number to the room and the staff; MuseumPests.net says floor area does not set it:

NPS Conserve O Gram 3/7, Setting the Traps:

“The number of traps per room depends on the size of the room, the number of windows and doors, materials stored in the room, and – most importantly – the number of staff available to check the traps. Setting a trap at every possible point in a room is useless if staff cannot check it on a regular (i.e. monthly) basis. Instead, start with the number of traps that one can reliably check, and add to that, if needed.”

MuseumPests.net, How to Monitor, Monitor Placement Scenarios:

“The total number of traps to deploy is not linked to square footage of the space; there is no easy formula to use.”

How often should traps be checked and replaced?

Weekly at first, then monthly in the current NPS guidance. The sources do not agree on the routine interval; see where the sources disagree.

NPS Conserve O Gram 3/7, Recording Catch Data:

“When initiating an IPM program or after treatment for an infestation, traps should be checked weekly. Under normal circumstances, it is common to collect traps and record catches monthly. Each site will determine the appropriate time interval between recordings in alignment with their complete IPM plan.”

NPS Museum Handbook, Part I, Ch. 5, E.7, p. 5:21:

“Step 9. Replace sticky traps at least monthly, when they become populated and dirty, or when the adhesive loses its tackiness, whichever comes first.”

MuseumPests.net, Monitoring, Monitor Trap Checking:

“Quarterly trap checking is a minimal goal to aim for.”

What should be recorded at each trap check?

The trap, the date, what was caught, how many, and at what life stage, plus the conditions:

NPS Museum Handbook, Part I, Ch. 5, E.7, p. 5:20:

“Step 5. Inspect the traps on a regular schedule and record the:

Trap number

Location of the trap

Date inspected

Species of pests found in the trap

Number of individuals per species found in the trap

Life stage of the species, unusual conditions, replacement date for the trap, climate control system, weather conditions and any other useful information.”

Life stage matters when reading the catch:

NPS Conserve O Gram 3/7, Interpreting Catch Data:

“The stage of development (larva or adult) may give insight into an infestation. Larvae indicate an active local infestation due to their limited mobility, while adult insects may be mobile, newly entering pests.”

A blank log with these columns is in the downloadable plan.

When does a pest catch in a collection require action?

Under the NPS standard, one pest in a collections area is enough:

NPS Museum Handbook, Part I, Ch. 5, E.17, p. 5:26:

“The action threshold for any area housing collections is the sighting of ONE larva or adult pest or any traces of the insect or organism.”

“While a museum pest is a far greater concern than a perimeter invader (which does not feed on collections), the action threshold is still met if a perimeter invader is found in an area housing collections.”

MuseumPests.net frames the threshold as something each institution sets from its own data:

MuseumPests.net, Monitoring:

“Monitoring provides data regarding the base level of pests at an institution, helps to identify active infestations, and can be used to determine the threshold of acceptable activity that is specific to each collection, zone, building, and institution.”

Should pheromone or light traps be used for routine monitoring?

The NPS sources say no. One MuseumPests.net fact sheet says yes for one species.

NPS Conserve O Gram 3/7, Special Attractants:

“Pheromones are not recommended for regular monitoring, as they are expensive, have a limited shelf life, and most importantly may lure pests into the space to create a problem where previously there was none.”

NPS Museum Handbook, Part I, Ch. 5, E.6, p. 5:19:

“Do not use pheromone traps and light traps routinely as there is a risk that they may attract pests into collections areas. Only use these traps on a case by case basis in consultation with a conservator and the regional curator.”

MuseumPests.net, Webbing Clothes Moth fact sheet:

“Monitoring for webbing clothes moth should be performed using sex pheromone lures specific for this species.”

How should incoming collection material be handled?

Inspect it, isolate it, and watch it before it enters storage or exhibit space.

NPS Museum Handbook, Part I, Ch. 5, E.16, p. 5:24:

“For all new objects, and new and returning loans: Isolate objects for a minimum of one month. Living pests can usually be detected within this period. However, be aware that insect eggs can be dormant for years depending on the species. Mold can also be dormant. Metal, glass, ceramic or stone objects should be thoroughly inspected and cleaned but do not need to be isolated. Inspect objects for signs of an infestation throughout the isolation period.”

MuseumPests.net, Isolation/Bagging:

“Bagging and monitoring objects suspected of being infested is not, strictly speaking, an IPM treatment as it does not eradicate insects.”

NEDCC Preservation Leaflet 3.10, Toxic Fumigants:

“In addition, routine fumigation of incoming materials is unwarranted and dangerous.”

How are rodents monitored in a collection?

With snap traps, together with exclusion.

NPS Conserve O Gram 3/7:

“Note that sticky traps are only for use with insect pests. Vertebrates such as rats and mice should be captured using snap traps, which is considered the most humane method of trapping.”

NPS Museum Handbook, Part I, Ch. 5, F.4, p. 5:30:

“Snap trapping, in conjunction with exclusion, is the most effective strategy for eliminating rodents from structures. Snap traps eliminate rodents and monitor for rodent entry, allowing evaluation of exclusion efforts.”

NEDCC Preservation Leaflet 3.10, Mice:

“Rodent bait should not be used in a cultural heritage organization. Rodent bait will generate carpet beetles in the bait itself.”

What non-chemical treatments do the sources describe for infested objects?

Freezing and anoxia, with a conservator involved before any object is treated.

NPS Museum Handbook, Part I, Ch. 5, E.16, p. 5:25:

“For infested objects: If an object is infested, determine the best way to treat the object, such as a freezer or anoxic treatment, in consultation with a conservator and the regional curator.”

NPS Museum Handbook, Part I, Ch. 5, B.4, p. 5:6:

“Freezing is the method of choice for treating most active insect infestations of objects. Use a freezer that reaches at least -4° F (-20° C) or colder.”

NPS Conserve O Gram 3/6, p. 1:

“The freezing process should not be used on a routine or preventive basis, but only when pest activity is evident or suspected. It is an interventive treatment and should not be employed indiscriminately.”

On anoxia, the sources give different exposure times:

NPS Conserve O Gram 3/9, p. 4:

“A two-week exposure at room temperature is sufficient for insect eradication.”

MuseumPests.net, Oxygen Scavenger Treatment:

“All developmental stages of insect pests can be eradicated if atmospheric oxygen levels within such an enclosure are maintained below 0.5% for a period of 21 days.”

On heat:

NEDCC Preservation Leaflet 3.10, Heating:

“In most instances, this type of disinfestation of collections is not recommended for cultural heritage materials.”

The downloadable plan sets out the freezer temperature and time table, the materials the sources say not to freeze, and each source's anoxia parameters.

What building conditions discourage collection pests?

Dry air, clean rooms, and a sealed building.

NPS Museum Handbook, Part I, Ch. 5, F.2, p. 5:27:

“Maintaining a stable temperature and RH. Keep RH below 65% to discourage moisture pests and be aware that high temperatures can support museum pests.”

NPS Museum Handbook, Part I, Ch. 5, F.3, pp. 5:28–5:29:

“Regularly vacuuming to minimize dust and other particulates, at least monthly. Use a vacuum cleaner with a HEPA filter instead of a broom to clean floors and structures, including floors, windowsills, walls and cabinet tops. Remove all traces of insects from the structure, such as frass, eggs, discarded skins, and discovered dead insects.”

NEDCC Preservation Leaflet 3.10, Occasional Invaders:

“Prevention of occasional invaders (as well as all pests) should be aimed at making the building envelope as tight as possible.”