---

Hello,
I am engaged in constant battle with "pests" that want to eat my reference collection of flies. Pests are Psocids, museum beetles and now some tiny mites! To kill pests I useParadichlorobenzene - PCB, which is carcenogenic, so I am not keen on using it, but there does not seem to be much alternative. I used to use Vapona insect killer sticks, which I cut into strips. These were excellent, as they lasted about a year in closed boxes. Sadly Vaponsa insect killer is no longer available, only the stuff that deters, but does not kill pests. Also, PCB does not last long before it needs replacing. This is a problem, as I have many boxes to curate and it takes a long time to refill the cells/containers with PCB. Time I could better use for identifying the flies I have caught, set and labelled.

Also, I use plastic lunch boxes and wooden storage boxes. I thought that plastic boxes would be best, as they seal really well, but today I have found tiny mites in one of these boxes, munching their way through some hoverflies! The box had no PCB in it, as I mistakenly thought a well sealed box would be safe.

So what does everyone else do?

Can anyone suggest a good modern text on curating a home reference colection of flies and other insects. What do other people use to keep pests away and kill them? How do you store your collection. All ideas welcome.

---

If you are the happy owner of a large deep-freeze, with enough space for a box (or more at the same time maybe), the solution may be simple AND very environmentally friendly: to kill all possible pests place a box in the freeze at a temperature of minus 30 degrees Celsius for a week. Make a schedule, so you roulate every box say every 6 months or so. That's all! You don't need any poison at all.
Need not say, that using boxes that close very well is the first important thing. And avoid "importing" already contained insects in the box, by first placing them in the freeze.

Myself, I don't even use a freeze (don't have one, won't buy me one), only wooden boxes that close very well. Some mites are found once in a while, but these seem not harmfull. I avoid placing any specimen in "open air" when not necessary. When I want to dry them, I place them in a box first.

Hope this helped! Good luck!

---

I do also use a freezer for pest control, but try to keep the number of freezing times per sample as low as possible for the following reasons:

1. Repeated freezing will slowly make the dried insects more brittle. I understand that many professional curators now dislike freezing for this reason.

2. Freezing/thawing cycles utterly destroy any remaining DNA. I have at times provided material for DNA sequecing. Dried insects can usually be used if they are not too old, but anti-pest freezing is a no-no.

In practice I use a unit system with transparent units, normally one small unit box for each species.
If the damage is limited to a single unit (and almost always it is), I remove only the affected unit, put it in a sealed plastic bag and then freeze the unit, insects and pests included, for a week or so.

Cheers,
Kahis

---

I agree to be a little carefull and not to freeze too often. If the boxes close well, there is hardly any need to re-freeze at all, to my opinion.
About destroying DNA-material: if you freeze only one or two times, it may still be okay. After about three years, any (diptera-) material has deminished quality of DNA-material anyway (if I understood correctly; correct me if I am wrong).
So, when used with care, this method is still to be preferred to my humble opinion.

Ciao, Andr

---

Is it absolutely necessary to freeze down to minus 30 degrees? Most domestic freezers only freeze to about minus 15-18 degrees. Is this likely to be cold enough to kill most museum pests? Laboratory Freezers go down to minus 40-50 degrees, but they are very expensive to buy and presumably expensive to run.

I am using plastic lunch boxes to store my stuff in. These have hinged lids, so they don't "ping" when they are opened. They appear to have a good seal, but in one of them I had hundreds of tiny mites recently. Perhaps these were already on the flies when I put them in the box. Fortunately, only three or four specimens are affected.

It's hard work keeping a collection in a good state. Amazingly, I once saw a collection of moths, that had bene kept in a shoe box for over twenty years and they were in perfect condition! I certainly would not try that myself.

---

When you mean these red-colored mites... yes, they must have come with the flies. If it was in only one of the boxes, the contamination most assumalbly came from inside the box.

When you want to freeze at -18 degrees C, you may have to keep them in the fridge much longer to be sure possible eggs or larvae are all killed. I wouldn't know when you are safe then. Maybe just try?

Boxes stored in a dark place seem to be easier contaminated than boxes stored in the light. Also humidity may play a role. As well as some luck

Anyway, I am not a specialist in this field. Maybe Kahis can add some info on this, since he is permanently living in a freezer....?
(I must say the summer of 2003 was very nice in Finland, though!)

Andr

---

http://www.ars.us...41&page=11
recommends -20 to -25C (well, actually it recommends -200 to -250C but an older version I have on my computer says -20-25). I'd guess a week at -18 should work well enough. There's long and very detailed paper on curating insect collections floating around on the net, but I cannot find the address rigth now.



I'd reply with a scathing remark, but my brain doesn't work before I've downed my daily shots of anti-freeze



Hey, you're one of the Dutch dipterists who were here on a bike tour in 2003, aren't you? Should've guessed... I never had a chance to meet you but I have heard wild stories from Tero Piirainen (just joking)

Global warming (and the coastal climate of Helsinki) sucks monkey balls. I miss the real crisp cold winter days of my youth in central Finland. This fall has been record-warm and my kite-snowboarding stuff hasn't been aired since April Brilliant sport tough, I wish the winter was longer here

---

I think the mites in my box are Flour Mites - Acarus siro. They are very small, almost transparent mites. They are hardy critters. Some of them have survived 3 days in a small box with Paradichlorobenzene crystals in it.

It's the freezer next for them. (evil laugh)

---

Hi Kahis.
Here is some proof that we really were there:
http://homepage.mac.com/lvanderleij/Menu1.html

And send Tero our greetings!!