• E-mail
• Print
• Comment
• Font Size
• Digg
• del.icio.us
• Discuss article

Scientists Kill Bugs by Freezing Them

Posted on: Tuesday, 25 March 2003, 06:00 CST

By TOMMY GRANDELL

STOCKHOLM, Sweden (AP) -- Two Swedish scientists have developed an environmentally friendly way of killing insects: Freezing them to death without poison.

A Swedish company, Sinterkil AB, received a U.S. patent in December 2002 for the process.

Field testing of the method, which uses carbon dioxide snow to kill harmful insects and their eggs, was started recently by Anticimex, a Swedish-based international pest control company, in the capital, Stockholm, and Goteborg in southwestern Sweden.

The snow-producing machine is a pressurized tube filled with carbon dioxide.

When the gas is let out through a nozzle it expands and converts to snow crystals with a temperature of minus 112 degrees Fahrenheit.

The nozzle, which was patented, shapes the snow particles as the gas is released, giving it the extreme cold. The snow sticks to surfaces quickly and completely, but melts quickly without damaging surfaces.

"We knew that bugs don't like cold. Having talked to scientists at the Goteborg Technical University, we realized that the snow must have the right quality to work," said biologist Bertil Eliasson, who invented the method with Per-Aake Hallberg. Goteborg, 295 miles southwest of the capital, is Sweden's second biggest city.

"When the insects are hit by the rapid-freezing carbon dioxide they die immediately. The cells simply burst from the cold," he said.

John W. Brown, an entomologist with the U.S. Department of Agriculture said the process could have some measure of effect on housepests, but wouldn't likely be good for widespread commercial use, say in crop dusters, especially in warmer climes.

"It'd melt too fast before it'd be effective," Brown said from Washington.

But it could be used inside a person's home, or a kitchen in a hospital, where insects that are close to people, like cockroaches or termites, could suffer from the spray, and quickly, too.

Eliasson said the procedure has several advantages compared with other conventional methods, including allergic reactions or the risk of insecticides leaching into the soil or water. Carbon dioxide causes no such problems.

According to Eliasson, the carbon dioxide used in the process is produced as a byproduct and dissipates quickly and harmlessly.

Some insects can withstand low temperatures by producing internal anti-freezing agents, like sugar, alcohol or proteins, in their bodies.

For instance, the common yellow mealworm, or Tenebrio Molitor, can increase its body temperature nearly 10 degrees to adjust for its environment.

"These protecting mechanisms require energy and time and this is why it is essential to chill fast," he said. "The faster the temperature drops, the better the result."

Sinterkil AB is based in Saevedalen, a suburb of Goteborg.

---

On the Net:

Sinterkil

More science, space, and technology from RedNova

Copyright © 2003 The Associated Press. All rights reserved. The information contained in the AP News report may not be published, broadcast, rewritten or redistributed without the prior written authority of The Associated Press.

More News in this Category