Because they are cold-blooded organisms, insects do not survive very well in
extreme cold or hot temperatures. Each insect species has certain
temperature and humidity conditions where it thrives. Although there are
some differences between species, it should come as no surprise that our
domestic cockroaches are best adapted to temperatures that we maintain in
our homes. They do not develop or reproduce when temperatures are too cold
(below 45degrees F) or too hot (above 115degrees F).

Hot and cold temperatures can be very effective in killing cockroaches, but
the adverse temperatures must be maintained for a period of time. Hot and
cold treatments are also most effective when they "shock" the cockroaches'
system. If cold temperatures are gradually lowered, insects have
physiological mechanisms that allow them to survive the cold. But, if you
take a jar of cockroaches from room temperature and put it into a sub-zero
freezer, the insects will be dead within a half hour. They just cannot adapt
that quickly.

Because cockroaches cannot survive temperatures above 115degrees F to
120degrees F, it is possible to use heat to eradicate cockroaches from
restaurants and food service establishments. After all heat sensitive
equipment is removed from the building, the temperature is increased to
about 140-150degrees F for five to six hours. It may not be possible for the
homeowner to increase the heat that much inside the home. But if a small,
infested appliance has many small crevices and can withstand 150degrees F
heat, a similar procedure can be used. The procedure is simple -- place the
heat-proof metal appliance in an oven, and after several hours at 150degrees
F, the roaches will be dead.

Cold can also be used to kill cockroaches, but it takes a prolonged exposure
to low temperatures to kill egg cases. Appliances or furniture can be left
in a garage when temperatures are below 0degrees F for several days. If
moving, leaving possessions in a truck or van will do the same thing.
Infestations in wall voids or indoor cavities can be subjected to extreme
cold by using a CO2 (carbon dioxide) gas canister. This will freeze a
localized area. Infested appliances can also be fumigated with CO2. Place it
in a plastic bag or other airtight container and inject carbon dioxide gas.
Allow freezing to occur. If a small item can be subjected to freezing, it
also can be placed in a freezer for several hours (or overnight) to kill the
cockroaches.



Jack

"Steve Christensen" wrote in message
...
In article , Rosalie B.
says...

x-no-archive:yes "Paul" wrote:

Errr....why not just go buy a chunk of dryice, toss it in and close
the
boat up?

One extra Oxygen molecule.

But it's not available is it? I thought it would be bound up and
unusable.
We spray it on a fire to choke it out so I figured it may have oxygen
but
it's not available. For that matter, water has oxygen too doesn't it?
But
you can't breathe it since it's not available.

I may be wrong ... I'm just wondering.

Carbon dioxide (from dry ice) is a simple asphyxiant. If it displaces
the oxygen in the air it will kill you, but it takes quite a bit of
it. You can be exposed to 30,000 ppm for 15 minutes and still be OK.

Carbon monoxide at 1500 ppm may lead to death, and the 15 minute
exposure limit is 35 ppm for an hour. This is because without the
extra oxygen molecule, CO has a 200 to 300 times great affinity for
hemoglobin than oxygen does. So even if there is enough oxygen
present, the CO will kick it off the hemoglobin and you will die. So
it isn't just a simple asphyxiant any more.


Roselie is correct about the CO being more than an asphyxiant. But the
object
of all this is to kill roaches, right? It's been awhile since college
zoology,
but I don't think roaches even have circulatory systems, let alone
hemoglobin.

I have frozen roaches in liquid nitrogen (when bored during a late night
in the
lab) only to have them thaw out and crawl away. Hardy little beasts.
Does
anyone even know whether depriving them of oxygen (with CO, CO2, N2,
whatever)
will kill them? I bet it's damn hard to do.

Steve Christensen