Deltathor

Gundula Tutt <gundula.tutt [at] freenet__de> writes

>Kasi Albert <albert.kasi [at] dpc__sa__gov__au> writes
>
>>A significant historic railway carriage with original carpets and
>>upholstery has an ongoing infestation of case-making clothes moths
>>(Tinea pellionella). ...
>
>>We have consulted with a pest control contractor, who has suggested
>>the targeted use of Deltathor Insecticide. Deltamethrin is a
>>residual pyrethroid (1%), used with propylene glycol (>1%) and
>>"other non hazardous ingredients secret (mostly water)" (to 100%).
>>...
>
>Did you ever think of a treatment with modified atmospheres like
>carbon dioxide? We have been using this successfully even on very
>large objects like a complete organ (measures approximately 17 x 8 x
>4 meters) and whole historic automobiles.

I am following this string with interest.  Of course, my first
reaction was similar to Gundula's "why not use a modified
atmosphere?", but then I considered the word "carriage".  A modern
railroad carriage is a fairly large object; it would take a lot of
CO2 to fill to 60-65%, and a lot of time, too.  Also, railway
carriages were not designed to be lightweights, so it could not be
easily moved or tightly wrapped.  Then I reconsidered:

Perhaps the carriage could be adequately sealed without fully
encasing it in a bubble.  Presuming an outdoors location, a greater
than normal leakage rate might be acceptable, and with a low enough
leakage rate, a continuous CO2 input would be able to maintain
effective anoxic conditions.  Once obvious points of leakage, such
as the doors, vents, and windows were taped or otherwise sealed, a
simple CO2 leakage test could be used to indicate if there was a
chance of creating a well-enough sealed environment.  Then, ultra
sonic or other leak location systems could be used to improve the
sealing.  As most of the carriage's interior is empty, much of the
volume could be filled with large barrier film bags containing
nitrogen, so the volume of CO2 needed would be minimized.  Or you
could "rent" the empty space to simultaneously treat other infested
items (helps to pay for the costs).

Costs would need to be compared, and some jurisdictions consider CO2
to be a fumigant, with limitations on use by the public, but CO2
anoxia does seem both a theoretically possible, and rather elegant
solution.

Jerry Shiner
Keepsafe Microclimate Systems
+1 800 683 4696


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                  Conservation DistList Instance 26:37
                Distributed: Saturday, February 9, 2013
                       Message Id: cdl-26-37-001
                                  ***