ELECTROMAGNETIC ENERGY AND SOUND FOR USE IN CONTROL 
OF CERTAIN PESTS 
S. O. Nelson, Research Investigations Leader, Agricultural Engineering Research Division, 
Agricultural Research Service, U.S. Department of Agriculture, and Associate Professor 
of Agricultural Engineering, University of Nebraska, Lincoln, and J, L. Seubert, 
Bureau of Sport Fisheries and Wildlife, Fish and Wildlife Service, 
U.S. Department of the Interior, Laurel, Md. 
Future possibilities for pest control utilizing 
electromagnetic energy and sonic and ultra- 
sonic energy have received more attention 
recently because of pesticide residue prob- 
lems. It is difficult to know what practical 
methods may be developed using energy from 
the vast electromagnetic spectrum or from 
sonic and ultrasonic sources, but a few such 
applications have already proven successful. 
Others are being tested in the field and studied 
in research laboratories around the world. 
Significant developments in pest-control meth- 
ods can be expected from this research, 
Some of the past accomplishments, current 
studies, and future possibilities for pest con- 
trol using electromagnetic, sonic, and ultra- 
sonic energy are reviewed in this paper. 
ELECTROMAGNETIC SPECTRUM 
Electromagnetic energy encompasses a wide 
range of radiation (fig. 1). All the electro- 
magnetic radiations from the low-energy radio 
waves through infrared, visible light, ultra- 
violet, X-rays, and gamma rays are basically 
similar in nature. All travel through free 
space with the velocity of light. The relation- 
ships between wavelength, frequency, and en- 
ergy of the quantum of radiation anywhere 
in the electromagnetic spectrum are described 
by the following equations: 
A= § 
and E=h, 
where c and h represent two fundamental 
physical constants, respectively, the velocity 
of light in vacuum and Planck's constant, 
AX is wavelength, v is frequency, and E is the 
energy of the quantum or photon. Thus, as 
wavelengths become shorter across the elec- 
tromagnetic spectrum, the energy of the quan- 
tum of electromagnetic energy increases. The 
energy of the quantum is frequently expressed 
177 
in electron volts, a convenient energy unit 
when dealing with X-ray and gamma-ray 
radiation. 
Several different units are used for wave- 
length depending on the region of the spec- 
trum. Meters and centimeters are common 
in the radio-frequency range, whereas the 
micron, millimicron (nanometer), and Ang- 
strom unit are used for the infrared, visible, 
and ultraviolet regions. 
The effects of electromagnetic energy on 
living matter have been studied in detail for 
certain phenomena, such as photosynthesis 
and the absorption of ionizing radiation, but 
much still remains unknown concerning the 
interaction of all types of electromagnetic 
radiation with biological material. Generally, 
however, the longer wavelength radiations 
produce heating effects and the shorter wave- 
length radiations produce chemical effects, 
including ionization of the atoms of absorbing 
media (9). 
Radio Frequencies 
Interest in pest control with radio-frequency 
(RF) electromagnetic energy has centered 
mainly in studies with insects. It has been 
speculated that insects might be controlled 
by radio waves of some particular frequency, 
which, by virtue of some resonance phenomena 
or selective absorption, would be effective 
in killing them. So far such deadly selective 
frequencies have never been found, nor has 
any conclusive evidence been presented to 
indicate that anything other than high-frequency 
dielectric heating is involved in the lethal 
action of RF electric fields on insects (136). 
On the other hand, neither has it been con- 
clusively shown that some specific effect other 
than heating cannot exist (102). Effects of 
heating and any specific nonthermal effects 
due to the electric field per se are difficult 
to separate. Recent attempts to do so using 
