1-5. MECHANICAL CONTROL
a. General. Mechanical control is the removal of pests by hand or by using
mechanical means to trap, kill, or keep pests out of an area. The most desirable aspect
of mechanical control is that results are usually seen very soon after the specific control
practice has been employed. On the other hand, the use of mechanical control can be
rather expensive in terms of time and effort. The amount of control attained is quite
often limited because this type of control is generally temporary in nature.
b. Mechanical Control Measures. Mechanical control measures include hand-
picking insect pests, then destroying them. Measures may also be more elaborate and
employ screens, bands of heavy oil, or other sticky substances as temporary barriers.
A good example is the use of window screens and bednets to prevent flying insects
from entering a house or sleeping area. Metallic barriers have also been used to control
arthropods. Strips of sheet metal, for example, have been used as fences to protect
fields of crops from crawling insects. Another example of metallic barriers used to
prevent damage from arthropod pests is the use of termite shields on wooden
structures. Other common types of mechanical control are fly swatters, mosquito
netting, and various types of traps, some of which kill with electricity.
1-6. PHYSICAL CONTROL
a. General. Physical control has many of the advantages and disadvantages of
mechanical control. Unlike mechanical control, which involves the use of machinery or
manual operations, physical control involves the use of energy factors in the
environment, such as heat, cold, light, sound, x-rays, and infrared rays, to kill pests or
attract them to a killing mechanism.
b. Manipulation of Temperature. Under certain circumstances, control of
arthropod pests may be effected by the raising or lowering of temperatures. The
lowering of temperature is usually not done to kill the pest in question, but to reduce the
rate of activity or development of the pest. Consequently, the rate of damage is
reduced or stopped. In contrast, the application of heat (120-180F) for three to four
hours has been used to kill insect pests in stored grain and grain products.
c. Radiation. Ionizing, ultraviolet, visible, infrared, and microwave radiation
have also been utilized in arthropod control with varying degrees of success. Of these,
Solar radiation, which is made up of several types of radiation, has been used to raise
the temperature of grain in some tropical regions. This has been accomplished by
spreading the grain out and exposing it to a large sunlit area. Ultraviolet light and visible
light have been used to attract insect pests to traps. By contrast, in storage areas
where lights are commonly used for security, lights that produce long wavelength visible
light (yellow-red) have been useful in reducing or preventing the attraction of insects.
The effectiveness of this technique lies in the fact that many insects are unable to detect
this light. Although ionizing radiation (alpha and beta particles, neutrons, gamma rays,