Michaela -
Let me add to what Tom is saying. There are several factors to balance when applying thermal treatments. First is the critical temperatures - and -20 deg C is usually manageable, and many of the tests have been done at that temperature. Second, the length of time can be determined by the density of the pieces in question. Herbaria and archive material are often treated as stacks or blocks of paper based materials - it takes longer for the center of the material being treated to get to the critical temperature. >From my own experience (I was involved in moving a collection in which >Thylodrias contractus was a known presence from an old building to a new >museum facility. We passed the entire dry biological (skins, taxidermy, >insects and skeletal collection) as well as other collections materials that >were susceptible to infestation through a walk-in freezer (we had one - we had >more time) that maintained -20 C. Each batch of collections that went through >were in the freezer for 1-3 weeks - generally 2 weeks. We successfully >knocked down the infestation by 99%. The collection went into new clean >cabinets. There have been no re-occurrences in storage for 10 years. One week at -20 should do it - but I usually recommend 2 weeks - especially for a mass treatment such as this. I recommend going to Tom Strang's article on the CCI web-site as the best way to determine the length of time and critical temperature. http://www.cci-icc.gc.ca/crc/articles/mcpm/chap06-eng.aspx#10c1a Good luck! Gretchen Anderson Conservator Carnegie Museum of Natural Hisotry ________________________________ From: pestlist-ow...@museumpests.net [mailto:pestlist-ow...@museumpests.net] On Behalf Of bugma...@aol.com Sent: Thursday, February 17, 2011 9:47 AM To: pestlist@museumpests.net Subject: Re: [pestlist] effect of freezing on Thylodrias contractus Michaela - First let me say you cannot compare the results of freezing cigarette beetles in herbaria materials to the Odd Beetle. Cigarette beetles in herbaria materials are usually found in dried plant materials in a plant press. The stack of plant materials in a plant press insulates the various stages of the beetle and will often result in a freezing failure. Many herbaria use heat instead of freezing to disinfest dried plant specimens. I can find no information in Tom Strang's paper, "A Review of Published Temperatures for the Control of Pest Insects in Museums", Collection Forum, 8(2), 1992, pp. 41-67, which refers specifically to the Odd Beetle. Being a dermestid beetle, I would assume it would take a week to insure complete kill at -20 degrees C. Tom Parker -----Original Message----- From: Michaela Berner <mber...@club-internet.fr> To: pestlist <pestlist@museumpests.net> Sent: Thu, Feb 17, 2011 6:27 am Subject: [pestlist] effect of freezing on Thylodrias contractus Dear colleagues, I am trying to get some specific information about the effect of freezing on Thylodrias contractus. In the actual situation of a museum (moving collections in difficult conditions, chest freezer of the museum overloaded) the institution planed to rent a freezer truck for treating a part of the collection. It seems that there will be no way to reach at least the temperature of -25°C in the available freezer truck, only -20°C. It was planed to treat one week at -20°C. I am concerned about this short time of treatment at on only - 20°C and I have doubts about the effectiveness, especially because eggs of Thylodrias contractus could be present. I would rather recommend, if lower temperatures cannot be applied, two-three weeks of treatment in order to compensate for the higher temperature. My doubts are reinforced by the experience of the Herbarium of the Academy of Natural Sciences in Philadelphia *: after treatment at -20° C for one week, larvae of Thylodrias were found (the targed beetle was the cigarette beetle); the cold was suspected to act as a natural trigger for the hatching of the eggs. -Has anyone studied the effect of freezing on Thylodrias contractus at different stages, different temperatures and different time of treatment? - Does any museum or institution noticed the reappearance of Thylodrias after freezing at only - 20°C? * "2004. Lesson in Integrated Pest Management (IPM): the herbarium of the Academy of Natural Sciences, Philadelphia". Society for Preservation of Natural History Collections (SPNHC). Sasha Eisenmann, James Macklin and Lucinda MC Dade, Department of Botany ANPS, Philadelphia. Poster presentation. Annual Meeting, NewYork city. Thank you in advance for any information Michaela Berner Biologist Consultant 14, rue Mayet 75006 Paris France tel: 00 33 /(0)1 44 49 99 81 The information contained in this message and/or attachments is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any system and destroy any copies. 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