Re: Choice of Argon vs. Nitrogen for the
treatment and control of insect infestation
In reference to the questionable statement, that
"inert" gases other than argon "are likely to
foster fungal growth" I think it is important to
clarify some issues regarding the use of either
gas for the control of insect pests and the
influence on microbiological activity. First of
all, both gases are entirely inert and scientific
research has proven their full efficacy in
eliminating all types of insect pests in all life
stages (given that specific conditions are being
maintained and controlled during treatment).
Second, fungal germination and growth depends
upon the substrate and ambient conditions.
Actually, most of us will intuitively know that
fungal and bacterial development only occurs at
higher humidity levels and where there is lack of
ventilation. Actually, the threshold level lies
somewhere around 70% relative humidity. Below
about 65% there is literally no risk for fungal
and bacterial proliferation. My third and
probably most important point is why nitrogen
anoxia will "foster" fungal growth although it is
known to be a strong inhibitor of microbiological
activity?? From scientific research we only know,
that some anaerobic microorganisms are able to
survive under "nitrogen anoxia" conditions. The
other more practical consideration is that during
anoxia treatments, the humidity inside the
"bubble" should always be controlled and
certainly kept below 65% RH, so the likelihood of
fungal growth inside the bubble under anoxic
conditions is absolutely zero, whether nitrogen
or argon is used. Furthermore, we are only
speaking about a treatment period of
approximately 30 days, the time needed to kill
all insects in all developmental stages.
Therefore, I think the issues of fungal growth
are much more related to the environment and
ambient conditions where the objects in question
are being kept at all times, rather than the
short period inside a bubble where they remain
during an anoxic treatment and where conditions
should be controlled anyway. In own experiments,
where I sealed wet paper and books in gas barrier
bags with Ageless oxygen absorbers, where the
remaining gas is mainly nitrogen, no fungal
growth was noticeable after about 50 days. The
bags were kept at about 20 - 22 °C and the
control that was sealed with atmospheric air
inside has shown noticeable fungal and probably
bacterial growth after about 72 hours. This in
itself proves that fungal growth is not an issue
with respect to the choice of the gas (argon or
nitrogen) when considering anoxia treatment in
order to eliminate insect pests. Additionally, it
may be interesting to consider cost, as argon is
a lot more expensive than nitrogen which is the
most abundant gas in our atmosphere. I would be
very interested in hearing other peoples comments on the subject.
Stephan Schäfer
--------------------------------------------------------
STEPHAN SCHÄFER Conservação e Restauração ltda.
Rua Manduri, 400 - Jd. Paulistano
01457-020 São Paulo, Brazil
Tel./Fax: 00 xx 11 3816-0489
Cel: 00 xx 11 8366-0230
e-mail: <mailto:[email protected]>[email protected]
---------------------------------------------------------
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Prof. Dipl. Rest. Stephan Schäfer
Universidade Nova de Lisboa (UNL)
Faculdade de Ciências e Tecnologia (FCT)
Departamento de Conservação & Restauro
2829-516 Caparica - Lisboa
PORTUGAL
e-mail: <mailto:[email protected]>[email protected]
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At 19:22 08.10.2010, you wrote:
Dear Dr. Diego;
The most reasonable option is to use anoxic
system, specially with argon protocol. This is
due to the fact other "inert" gases are likely to foster fungal growth.
Please give me a call when you can, and I'll be
pleased to help you as I'm using argon's anoxia
systems here in Brazil for over ten years.
Best regards,
Ulisses Mello, Dip. Cons., PG
Art Care do Brasil
Mobile: +55 21 98979074
Office: +55 21 25587749
2010/10/8 Revelez, Marcia A. <<mailto:[email protected]>[email protected]>
Forwarding this for a colleague. Please respond to Deigo (email below).
Thanks!
----------------------------------------------------------------------------
Marcia A. Revelez
Collection Manager
Department of Mammalogy
Division of Collections and Research
Sam Noble Oklahoma Museum of Natural History
University of Oklahoma
2401 Chautauqua
Norman, OK 73072
Phone: 405-325-7988
Fax: 405-325-7699
Begin forwarded message:
From: Diego Astua de Moraes
<<mailto:[email protected]>[email protected]>
Date: October 8, 2010 12:43:07 PM CDT
To: <<mailto:[email protected]>[email protected]>
Subject: Fumigating cabinets - bug infestation
Reply-To: Mammalian Biology
<<mailto:[email protected]>[email protected]>
Hi all.
In a matter of days bugs have started to show
in our skin cabinets. According to our
entomologist they should be beetles that feed
on wood or cellulose (sorry if the family names
escapes right now), but other entomology
curators have seen these eating almost
everything in other regions of Brazil.
Regardless of what they are, I want them all dead now!
In short, I need to get rid of them as quickly
as possible, before the damage increases.
Freezing is unpractical at this point, too many
specimens and too little freezer space (we are
talking about 3 cabinets with beetles
confirmed, and about 3-4 others still intact,
but that I want to protect as well). I´ve had
suggestions of fumigating the entire cabinets
using PDB balls, but I can´t seem to be able to find those here quickly.
Our entomology colleagues have suggested to use
ethyl acetate and seal the cabinets so that it
kills adults and larvae. My main doubt is if
there is any knowledge that this may damage
severely the skins (because if i don´t do
anything quickly they are being damaegd
anyway!), and if this would be enough. I am not
sure about the amounts, I´ve read of a cotton
ball in ethyl acetate to fumigate a small
container to kill the ectoparasites of a single
specimen, bu what about a whole cabinet? And
how long should it be kept sealed? Or are there
any other quick solutions, remembering that
many "easy" solutions are now radily found around here....!
thanks for any help.
Diego
Diego Astúa de Moraes, D.Sc.
Departamento de Zoologia - CCB
Universidade Federal de Pernambuco
Av. Professor Moraes Rego, s/n.
Cidade Universitária
50670-420 Recife, PE
Fone(fax): (81) 2126-8353
email:
<mailto:[email protected]>[email protected]
m - <mailto:[email protected]>[email protected]
<http://www.ufpe.br/mastozoologia/>http://www.ufpe.br/mastozoologia/
