Roaches in the Microwave

I read your comment on roaches in a microwave. I must confess that with nothing better to do in my spare time I decided to address the never ending battle against cock roaches in the the great USA. Contrary to your suggestion that the microwave in question might have been a Popiel the one I used at the University of Tennessee Center for Health Sciences was no Popiel. As a matter of fact it was a microwave generator capable of delivering 5000 watts. At the maximum power level the microwaves have NO appearent affect on the more common German Cock Roach. I did note that the container used at first eventually heated up enough to kill the varmits but it definitely was not the microwaves. My theory is the same as the author of the question you commented on. A roach has liquids inside its exo-skeleton that should boil. The appearently do not do so in the presence of microwaves. I am still experimenting on this delima but I suspect the answer lies within or upon its exo-skeleton or “shell”.
One house hold chemical that most unwanted creatures will avoid is table salt. A well soaked rag with salt saturated water wiped across a surface will repell roaches even after it dries.


Welcome to the board, Hayden. I see you’re a do-it-yourself kind of guy, if not exactly St. Francis…

Anyway here’s a link to the column you’re referencing. I don’t have a microwave or roaches at home (I hope…), so maybe others will chime in with their own experiences.

The reason? Surface-to-volume ratio. Things absorb microwaves as a function of their volume, but convective cooling is a function of surface area. For very small things, like cockroaches, the heat lost through surface cooling balances the heat gained from RF absorption at a considerably lower temperature than larger objects.

Are the roaches immobilized?

They may be able to detect the absorption of the microwaves and move to a location where they feel less heating.

Did St. Francis’ remit actually cover insects, then? Go on, tell me there’s a patron saint of insects! :slight_smile:

Just as a contrary data point …

As a kid living in northern Utah, I had a friend who lived in a giant old house that was very bug-friendly, and both of us were extremely bug-phobic but also pretty squeamish about squishing them, so he would kill them by trapping them inside a glass and then putting them in the microwave. I saw him microwave several hundred roaches, spiders, beetles, boxelder bugs, and centipedes over the years, and every one of them died within five seconds of the microwave being turned on.

This does not sound like the act of a true entomophobic, who will decline to pick up a bug either directly or indirectly. The only response Mrs. Fear has to bugs (beyond calling me) is to spray them with oven cleaner or hair spray or carpet foam until they are no longer visible. This accounts for the odd stains on our walls.

Heh heh … what about a bug-on-your-skin-and-bug-guts-phobic?

I take your point that there are “safe spots” in microwaves (the ones without turntables at least) but in my experience (using cat food; I LIKE roaches, although I did accidentally put a Giant Malaysian Hissing Cockroach through a washing cycle once - it survived, at least temporarially) small volumes of material get hot in a few seconds - I wouldn’t have thought there would be enough time for something to find a cooler area, especially as the air inside the microwave itself will probably not change that much in temperature (microwave ovens bascially work by heating water, as I understand it)