Fumigation Question

[jhyatt]

Hello all,

I have a question for those who fumigate/protect their lep drawers with dichlorvos ("no-pest strips"):  Assuming you're using the commercially available yellow plastic formulation that's 18.6 % dichlorvos (I get mine at Tractor Supply Co.), how big a piece do you put in an average-sized, fairly tight bug drawer?  I generally cut a chunk that's about 1/2 to 1 inch square.  I'm sure that that is overkill.  The package says the whole strip will fumigate 1200 cubic feet.  My drawers are roughly 0.7 cu. ft. in volume, so if I followed the labeling, I should put only 1/1714th of the entire strip in a drawer, if my arithmetic is correct.

That would be impossibly small to cut and pin, of course.  And the label doesn't say how long the strip will keep 1200 cu. ft. fumigated, so I can sort of justify using considerably more.  But does anybody have a good concept of how much is enough?

Also, how often do you replace your fumigant strips?  I find that after about 3-4 years in a drawer, they become rather pale, whitish-yellow and a bit shrunken, so I replace them when they look that way.  Again, I have no real knowledge of whether they're still effective at that stage or not.  I've never had a pest problem in a drawer containing a piece of dichlorvos, no matter how old it is. 

So what's your practice in using this material?  An do you base your practices on a hunch, or do you have real knowledge about the diffusion rate of dichlorvos from the strip material?

Cheers,

jh

[Paul K]

I use no pest strip for only for about 5 years so can’t be of much help.
I cut them to 5x5 mm pieces and I suppose they are large enough.
I too change them when they are drying out, become pale yellow.
Never have any problem.

I must add that I had problem with rice weevils due to storage of rice and rice product in my apartment and I found few times dead one inside drawers and cabinets which I suppose were killed by strip.
Since then I keep all rice in the fridge and have no problem.

When I bought them I think it said on them they are good for 3-4 months but that is for open spaces like garages or attics

[deliasfanatic]

I've been using it for about 25 years with no problems. I used to do what you're doing, i.e. cut up the yellow No Pest Strip into pieces, until I found a company in Michigan that sells Vapona pre-cut into small squares. The latter are 1/2" x 1" and about 1-1.5mm thick. When I cut my own, I used to do about 1/2" x 1/2", but it's hard to cut evenly. The pre-cut pieces are so much more convenient that I would no longer consider cutting my own.

Here's a link to their catalogue. It's listed as "Hercon Vaportape" at lower right of page 9.

www.greatlakesipm.com/CATALOG%2018.pdf

[jhyatt]

Thanks for the link, Deliasfanatic. I've bought Sesiid pheromones from Greatlakespm, but had never noticed the pre-cut vapona strips. The slabs I buy are intended to be hung in a barn or stable, and are about 6mm thick and hard to cut up - tough to get a pin through, also!

How long do you let these thin pieces stay in a drawer before replacing them? I often let mine go 5 years or so; I usually replace an old one only when opening the drawer to add or remove a specimen.

Cheers,
jh

[deliasfanatic]

I replace them every 4-5 years. They've gone longer than that with no ill effect, but that may be tempting fate.

Agreed, it's hard to put a pin through them. I used to do that, but now I place the piece butted into the corner of the drawer, then place a pin (top of pin slightly angled toward the center of the Vapona piece) on the two sides that don't touch the drawer edge. The angle keeps it from riding up the pin or slipping out if I tilt the drawer.

[Paul K]

I drill the hole for a pin, there is no way I could push pin thru

[billg]

I’ve used them (vapona strips) for decades and w great success.  My pieces are cut into abt 1/2” x 1/2” and one edge is cut at a 45 degree angle.  By doing this, I can easily push a pin through abt half way through the angled edge.  Also....I use those yellow headed sewing pins for this for two reasons. First, they’re stronger and have a large yellow pin head to use to push with.  Second, the yellow head always is showing so I don’t accidentally damage a wing whereas as regular or insect pins can easily be hidden/missed when putting in/positioning specimens, and, before u know it, you’ve split a wing.  I usually change out the pieces every two or so years.  If I’ve opened a drawer frequently, I might do it sooner.  

Preventing pest entry is critical.  All my mounted specimens are put in my laboratory incubator for a few days at 115 degrees.  This assures me that no living matter is riding along in or on the specimen when putting it in my drawer.

Lastly, I take a brush with cedar oil on it (diluted) and “paint” a strip of oil along the lip of the drawer to act as a deterrent to entry from outside the drawer.  This is done once a year.

Results.....no dermestid infestation for many many years.  Btw....my older strip pieces being replaced go into papered material containers, spare parts tubs, or rikers when I occasionally use them.  A taped (w electricians tape) shut riker mount w a piece or two of vapona will keep pests out for many years.  When my mom passed, I came across a riker I made for her when I was a teen in the 1970s which was totally pest free after 38 years.  

[jhyatt]

I have a small accumulation of homemade Rikers (no two the same size), all made by a Canadian collector in the 1930's and 1940's. No tape seals, and I've only opened a couple of them to take out and pin some really good things I wanted in my pinned collection. Data is on the back of the Rikers, behind each specimen.

Not a single specimen in these Rikers shows any pest damage. But in the ones from which I removed specimens there was, just beneath the body of each bug, a very small piece of white cardboard or thick paper. I presume that the long-gone collector adsorbed some sort of insecticide onto these papers; I have no idea what it might be. Nicotine? Arsenic? There weren't very many choices back then, but whatever he used has worked!

jh

[Ed]

I place my fumigant into small drug sized ziplock baggies and put them into my specimen boxes to prevent it from tumbling around the box. I assume it would be much easier to pin it within a small bag into the drawers.