Page 169 - AG 7-2011 Revised 2016

C. Granules are dry, rather coarse particles compared to dusts. Granules are generally used in
soil treatments.
D. Resin Strips are plastic strips containing insecticides, which release vapors to control flying
insects in structures.
E. Pastes are used as baits.
F. Oils are used as dilutants in place of water where rapid kill of insects is needed.
G. Invert Emulsions are mixtures of water in oil. These are hard to use and are not generally
recommended for service technician use unless he has proper training and equipment.
H. Lacquer-pesticide combined with lacquer to create a long residual.
I. Micro-encapsulated-encased droplets of the active ingredient in permeable plastic capsules.
The pesticide escapes through the capsule wall over a period of time, giving extended control.

CLASSES OF PESTICIDES

The following is a discussion of the most common chemical classes and some special back-
ground information on each one. Specific product examples of each chemical class will not be
given because your company will decide which products you are most likely to use.

Chlorinated Hydrocarbons
In 1942 a new pesticide was discovered called DDT. It was the first really long-lasting pesticide
that could be used safely. Although it was later used as a rodenticide, it started out being used
as an insecticide. DDT was the first in a chemical class of pesticides called chlorinated hydro-
carbons. These chemicals contain such elements as chlorine, oxygen, hydrogen, and carbon.
When these are chemically joined together they form a compound which has unusual character-
istics all its own. Chlorinated hydrocarbons are still very effective; however, most of them have
had their uses restricted to a few specified types of applications. Most were limited to control of
wood-destroying pests. These are stomach poisons primarily; however, they can also take ef-
fect by contact. As a matter of fact, they act fastest on humans through absorption through the
skin, although breathing or eating them is also very dangerous.

Organic Phosphates
These compounds act on the nervous system. They are almost exclusively insecticides. They
block the formation of a chemical in the insect’s body (called an enzyme) which is important to
the insect’s nerve reaction. The organic phosphates formerly used in structural pest control
were not too hazardous because of the low concentrations and the nature of those being used.
However, they can be dangerous by skin contact, swallowing, and even by breathing the vapor
in large quantities. As a rule, they do not last as long as chlorinated hydrocarbons. Once used
and exposed to air or sunlight or moisture, they tend to break down into harmless elements,
usually within a few days to a few weeks. A wide variety of insects were once effectively con-
trolled by this chemical class, which has now been greatly restricted.

Carbamates
Carbamates were a newer class of insecticides. Like organic phosphates, they act on the ner-
vous system. They can enter a pest or animal body by breathing, absorption through the skin,
or eating. Although most carbamates are not highly toxic, some are, so reading the label care-
fully is very important. Carbamates, like organic phosphates, were once used to control a wide
variety of insects.

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