An inexpensive acoustic device has been put to a new use - locating insects beneath the soil surface.

Portable acoustic sensors found insects within three minutes over distances of 4-12", depending on soil composition and frequencies of the sound pulses. USDA-ARS scientists and colleagues conducted the tests in Florida, Oregon, and Puerto Rico on various insects.

The acoustic technique uses sensitive instruments to pinpoint insect locations. These sensors convert vibrations into electrical signals. The researchers developed profiles for various insects and background noises including wind, airplanes and motor vehicles.

In ideal field conditions - low levels of background noise - the researchers found insects within the 12" range with 100% accuracy. In adverse conditions, the technique was still 75% accurate.

The USDA workers point out that the method is inexpensive and doesn't require digging or root removal. They say it "may prove useful to growers intent on using integrated pest management systems to lessen the impact of a variety of insect pests on farm productivity."