Hi Pam;
The method we use is to bag items to be frozen, put them in the freezer
where they sit for at least two days, bring them out for a day, then put
them back for at least another two days. How long they stay in the
freezer really shouldn't be much consequence; what the first freezing
does is make the bugs think winter's coming on, they go into
"hibernation" and manufacture glycol that fills their bodies and keeps
them from freezing. The warm-up period simulates the end of winter, so
they "wake up." This is where the timing is most important--you want to
hit them with the second freezing as their emerging from hibernation;
the first hibernation and re-emergence takes a huge biological toll on
them, and you want to force them into another "winter" before they've
recovered enough to re-fill themselves with glycol.
You're right to not use a frost-free freezer; to make sure you kill
just about anything that may be infesting your collections, you want
your freezing cycles to be down around -28 degrees C. Some household
chest-type freezers will do this (it's what we use). Warmer
temperatures may kill some species, but then again, might not. If you
have to use "the great outdoors" as your freezer and it may not get this
cold, make sure you get as much air out of the bags as possible (air
pockets will insulate the bugs against the cold). We use a vacuum to
suck the air out of the bags, then seal them with tape.
------------------------------------------------------------
Tim McShane, Assistant--Cultural History
Esplanade Museum
401 First Street SE
Medicine Hat, AB T1A 8W2
Tel: (403) 502-8587
[log in to unmask]
>>> Pamela Silvestri <[log in to unmask]> 1/25/2007 9:44 AM >>>
Does anyone know how long a period of time objects should be in freezer
treatment to kill clothes moths? This is a wool baseball uniform and a
cap (the
cap has a leather band). I brought them over to a nearby University Ag
extension program services for identification and the moths are pupa
stage.
I've been referring to NPS Conserve O Grams 3/8 and 3/6
_http://www.cr.nps.gov/museum/publications/conserveogram/03-08.pdf_
(http://www.cr.nps.gov/museum/publications/conserveogram/03-08.pdf)
3/8 recommends 2 weeks and 3/6, 6-10 days. 3/6 recommends warming after
48
hours and re-freezing. 3/8 recommends deep freezing. I decided against
placing
these items in my home freezer - because the Conserve O Gram mentions
an
issue with the temp changes in frost-free freezers.
All objects are in ziplock freezer bags, in a plastic bin and are in
safe
storage outdoors. I should be able to count on freezing and below
freezing temps
for the next several days. If possible, I'll go with a longer period
of time
(2 weeks) to increase the chance of killing the pupa.
Does anyone know if pupa stage moths should be treated differently than
larvae? Would one be more sensitive to freezing than the other? Also,
how do I
adequately clean the glass case these objects were in? And, there are
leather
objects (shin guards, boxing gloves, cleats) that have cloth
lining..but they
don't appear to be affected by the moths (they are still in the case
for now).
I have concerns about freezing the leather - how should I clean/treat
these
objects?
As always, I'd appreciate any information the list can provide. Pam
Pamela Silvestri, Volunteer Assistant Museum Director
Northeast States Civilian Conservation Corps Museum
Shenipsit State Forest Headquarters
166 Chestnut Hill Road
Stafford Springs, Connecticut 06076
Telephone: (860) 684-3430
e-mail: [log in to unmask] or
[log in to unmask]
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