Thank you for all the interesting responses. We will consider the density of the pieces to be treated under this conditions, assume that Thylodrias react like other dermestid beetle and hopefully get rid of the infestation. Michaela Berner -----Message d'origine----- De : pestlist-ow...@museumpests.net [mailto:pestlist-ow...@museumpests.net] De la part de Anderson, Gretchen Envoyé : jeudi 17 février 2011 17:06 À : pestlist@museumpests.net Objet : RE: [pestlist] effect of freezing on Thylodrias contractus
Jerry That was the original thought, however more recent research out of CCI and others have shown that it is not necessary, more time consuming with more potential damage to objects. Fast freeze and slow thaw is still preferred. And of course, double bagging to reduce/eliminate extreme relative humidity fluctuation, and danger of condensation. It is also best to insert a temperature probe with any thermal treatment (hot or cold). However what is best is not always possible. Gretchen _____ From: pestlist-ow...@museumpests.net [mailto:pestlist-ow...@museumpests.net] On Behalf Of Jerry Shiner Sent: Thursday, February 17, 2011 10:58 AM To: pestlist@museumpests.net Subject: RE: [pestlist] effect of freezing on Thylodrias contractus My understanding is that freezing to kill infestations is usually a two stage process, with the first freezing followed by a warm up, and then completed with a second freezing to kill any larvae that emerged after the first freezing. I'm presuming that this may be needed even if the insects are subjected to extreme cold. I know that heat treatments can be controlled by inserting a temperature probe (into the very centre of the most thermally resistant objects) and heating the objects until the desired temperature is reached. I see no reason why this can not be done for freezing, especially if the job is large and the purchase of appropriate measuring instruments is justified. js Jerry Shiner Keepsafe Microclimate Systems 800 683 4696 www.keepsafe.ca <http://www.keepsafe.ca/> i...@keepsafe.ca Specializing in the design, procurement, and installation of environmental control systems in museums and archives. -----Original Message----- From: pestlist-ow...@museumpests.net [mailto:pestlist-ow...@museumpests.net] On Behalf Of Anderson, Gretchen Sent: Thursday, February 17, 2011 10:36 AM To: pestlist@museumpests.net Subject: RE: [pestlist] effect of freezing on Thylodrias contractus 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 Strangs 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. Any views expressed in this message are those of the individual sender. 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. Any views expressed in this message are those of the individual sender.
