Fumigants

[Nick Greatorex-Davies]

Jonathan wrote:

>>Those damned dermestids love to much on my specimens too -  and it's
>>usually the rare/irreplaceable/exceptional ones! Nothing beats PDB
>>(paradichlorobenzene) for getting rid of these as well as Carpet
>>beetles (another long time foe!)

Doug Yanega wrote:

>Sorry to burst your bubble, but that's just not true. PDB is mostly a
>repellent, and is only marginally toxic to dermestids, mostly in the larval
>stage (Carpet Beetles *are* dermestids, incidentally - you've got only one
>foe, not two). Accordingly, several things *do* beat it. See the following:

Are we talking about the same chemical here? : 1,4-Dichlorobenzene (Paradichlorobenzene C6H4Cl2).

I have always found it to be totally effective against Dermestid (notably Anthrinus verbasci) infestation in insect collections. It certainly kills all the larvae within days and they stop feeding almost straight away in an infested storebox or cabinet drawer and the fact that if I use it - I don't get any problems with Dermestids, but if I don't - I do, is proof enough for me. Not only have I found it to be an effective preventative, but also an effective cure against Dermestids, Ptinus tectus (Ptinidae) (in one instance where stored unmounted lepidoptera samples were infested), Hoffmannophila pseudospratella (Brown House Moth)(completely decimated one box I had not treated for some time - so treatment came a bit late, but it killed them all) and Psocids (only ever a very minor problem).

Jonathan also wrote:

>I also line the drawers with a layer of PDB under the pinning boards, so that
>the fumes in a closed cabinet will be chokingly strong - this will
>assure that no pests will enter or survive, as long as the PDB is
>present (it sublimes and so must be periodically replenished). Just
>don't breathe the fumes if you can avoid it; they are known to cause
>health problems. Hope this helps.

PDB has the advantage of (purportedly) not being a carcinogen. According to information supplied under health and safely regulations here, its medical effects are as follows:

Moderate toxicity. Moderate irritant.
Possible long term effects
I (Internal / Intestine): Nausea.Vomiting. Abdominal pain
S (Skin): Mild skin sensitizer. Redness. Burning. May be absorbed through skin.
E (Eyes): Pain. Redness. Watering.
R (Respiratory): Irritant. Cough. Shortness of breath.
X (?) LIV;KID (liver;kidney): Non-specific injury

I have been using PDB for many years (since the late 60's early 70's) and for years I had my collections in the office where I worked, though now they are in a separate room. As far as I am aware, I have suffered no ill effects, except noticing some slight temporary irritation to my lungs (occasionally followed by a bit of coughing) when I have been applying crystals to lots of store boxes / cabinet drawers at one time, or had my head close over an open box or drawer for any length of time, that had recently had crystals put in it. I have also experienced a bit of temporary mild skin irritation if I have handled it. With most of these things it seems ill effects only occur with excessive exposure. If used sensibly it should cause no health problems, i.e. keep specimens in a room that is not lived in, examine specimens in an open box or drawer in a well ventillated room and do not handle the crystals with bare hands. All these things I have ignored in the past .... but I'm still here ... for the time being any way!

Kind regards

Nick Greatorex-Davies

Mr J Nick Greatorex-Davies
(Butterfly Monitoring Scheme co-ordinator)
Institute of Terrestrial Ecology
Monks Wood
Abbots Ripton
Huntingdon
Cambridgeshire PE17 2LS  UK

Tel: (+44) (0) 1487 773 381
Fax: (+44) (0) 1487 773 467
E-mail: n.greatorex-davies at ite.ac.uk