Fumigation of motor collection

Kasi Albert <albert.kasi [at] dpc__sa__gov__au> writes

>A large motor collection is currently having a problem with a spider
>infestation ...
>...
>... The Pestigas MSDS in particular warns of
>potential problems if it comes into contact with plastics or
>oil-based paints. The fumigants are most likely to be applied as
>sprays or fogs.

When the question of spraying in the collection arose here, what I
remembered from my training is that pesticide sprays are not
recommended, and in reading up on the topic this was confirmed. The
museum spaces can be sprayed with pesticides, but it is not
recommended anywhere where it will come in contact with collection
items. The pesticide is a dust which settles on surfaces, and has an
oily sticky quality to it. Although the active ingredient in the
dust breaks down in a couple of weeks so that it is no longer toxic
to insects, the dust remains, and dusts on metal surfaces promote
corrosion.

I have in the past come across brasses and other metals objects that
were dull, matte and/or tarnished looking on the upper surfaces, but
shiny on undercut areas where dusts would not settle. I suspect, but
cannot confirm, that this is a legacy from the use of pesticides
around these objects.

On non-metal surfaces the dust is still a concern because it makes
things dirty, attracts more dirt, and darkens surfaces. The dirt
cannot be removed effectively from porous surfaces.

Depending on the chemicals present, some pesticides will interact
with paints, finishes, glues and synthetic materials, softening them
or dissolving them and can cause such problems as hazing, blooming,
penetration of dirt into surfaces, sagging or weakening, failure of
glues and finishes, as well as possible chemical degradation
reactions. If yours is a collection of motor vehicles there will be
plenty of metal, paints, finishes and synthetic materials that could
potentially be affected.

My understanding of your problem is that the spiders are a potential
hazard to the humans, but not a significant threat to the artefacts,
other than being food for other vermin. I come from a land of
non-poisonous spiders so my reaction would be to improve
housekeeping and do more dusting, rather than spray poisons about,
but perhaps for you there is actual hazard involved in this, not
just the "ick" factor. Still, I would recommend doing what you can
to discourage pests entering (better seals on the building, removal
of food, water and other attractants), and a strict housekeeping
regime before advocating pesticides.

Valerie Tomlinson
Conservator
Auckland Museum
Tamaki Paenga Hira
The Domain
Private Bag 92018
Auckland 1142
New Zealand
+64 9 306 7068


                                  ***
                  Conservation DistList Instance 25:11
                 Distributed: Saturday, August 20, 2011
                       Message Id: cdl-25-11-010
                                  ***