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Subject: Carpet beetles

Carpet beetles

From: Paul Storch <paul.storch>
Date: Thursday, April 23, 1998
Allyn Lord had an inquiry in Cons DistList Instance 11:85 regarding
the 'sudden' appearance of a carpet beetle infestation and how to
respond to it.  It sounds like she and the Rogers Museum are taking
a very good preventative conservation approach to collections care,
however, there is some information that is lacking from her
description of the situation.

I would assume that the insects showed up in traps in areas other
than the basement, because Allyn implied that although the other
areas of the building are being use for exhibits and education, the
basement collections storage is still empty.  Therefore, it would be
safe to conclude that the source of the insects is on the upper
floors.  Not to eliminate all other possibilities, however, one
should also look into the possibility that the source of the
infestation might be a dead animal inside one of the walls.  She
stated that "IPM is being done throughout the building", but some
PCO's ideas of IPM is slightly different than what conservators
consider IPM, and they may still use poisons for rodents.  Is there
a bat colony in the attic?  That could be a source of the
dermestids.  Have all of the trapped insects been identified
properly?  There may be more than one species present. Knowing that
would also help design an intervention program that will be

She should look into what has been recently brought into the museum
in terms of infestable collections, and when they were brought in.
To summarize:

    *   Take a multi-pronged approach to solving this problem:

        1.  Find the source of the infestation(s):

        *   Look at the building itself for an internal source (e.g.
            dead rodent and/or bat infestation.

        *   Investigate what came in a when in
            collections/educational objects.

        2.  Continue monitoring the traps.

        *   Identify all species in the traps.

    *   Once the two major questions of what and where have been
        answered, then:

        1.  Work with a licensed pest control operator (PCO) to
            design an eradication and long-term control
            strategy for the species involved.

        *   This will probably involve chemical applications
            that are the most effective while being the least
            damaging to collections (you can check with a
            conservator who has had experience with this before;
            contact me off-list); and/or non-chemical means such
            as freezing and anoxic treatment of individual
            infested objects. The building spaces themselves, in
            some areas, will probably need to be treated with a
            pesticide dust in order to control the adult stages.
            Accessioned historic objects must be treated in the
            least obtrusive way possible.

        *   Structural modifications to the building might have
            to be done, esp. if there are bats or other animals
            getting into air spaces and the walls.

        *   The collections acquisitions/ educational object
            policies might have to be rewritten to allow for
            inspection and quarantining of all objects prior to
            introduction into the spaces.

I hope that this has given you an idea of how to approach this
problem. Please let me know if you have any further questions or
need more specific advice.

Paul S. Storch
Objects Conservator
John and Martha Daniels Objects Conservation Laboratory (JMD-OCL)
B-109.1, Minnesota History Center
345 Kellogg Blvd West
St. Paul, MN  55102-1906
Fax: 612-297-2967

                  Conservation DistList Instance 11:86
                  Distributed: Monday, April 27, 1998
                       Message Id: cdl-11-86-002
Received on Thursday, 23 April, 1998

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