compounds found in the bacterial species Saccharopolyspora spinosa, can be used
in water treatment [8]. Use of organic botanical insecticides like azadirachtin or
Neem (tree extract) can be combined with diatomaceous earth.
One can classify pesticides according to usage, as below.
1. Stomach poisons
These are absorbed through the insect’s alimentary tract and are applied before
an insect feeds. Most of the stomach poisons are inorganic chemicals and familiar
examples are the arsenicals and sodium fluorosilicate.
2. Contact poisons
These kill by direct contact with some part of the insect’s body.
(a) The contact may be made by direct application of sprays, dusts, or aerosols.
An example of this type is parathion.
(b) The pesticide may be applied to a surface on which the insect passes (residual
treatment). The chlorinated hydrocarbon compounds are insecticides of
this type.
(c) The pesticide may be applied in a closed space as a fumigant. Among these
are hydrogen cyanide, methyl bromide, paradichlorobenzene, phosphine,
sulfuro chloride, and carbon dioxide.
3. Systemic poisons
These compounds are taken up by the plant or animal at the point of application whereby they are transported to another part of the body. Some of the
organophosphorus insecticides are systemic poisons.
Most of the organic pesticides act as nerve poisons of the pest in question. They
induce continuous nerve action through inhibition of cholinesterase, producing
tremors, convulsions, and, eventually, death. Since the biochemistry of pest insects
is no different from that of beneficial insects (e.g., honeybee or preying mantis), and
very similar to that of higher animals, including humans, these chemicals must be
used very cautiously.
In contrast to the nerve-poisoning role of nerve poisons, the chlorinated hydrocarbon insecticides interfere with the organism’s production of enzymes, resulting in
a variety of abnormalities such as the thinning of eggshells and subsequent unsuccessful development to maturity, and the elevation and depression of hormone
levels, producing erratic behavior.
While an important and active area of research, this chapter will only include a
very brief discussion on human health risk assessment of acute or chronic effects
chemical pesticide (Sect. 9), as is largely beyond the scope of this work.
5 Pesticide Control of Organisms Pathogenic to Humans
Organisms that are pathogenic for human health widely vary, and are a critical drain
on human productivity and well-being worldwide.
396
L. S. Clesceri and E. J. Clesceri
in water treatment [8]. Use of organic botanical insecticides like azadirachtin or
Neem (tree extract) can be combined with diatomaceous earth.
One can classify pesticides according to usage, as below.
1. Stomach poisons
These are absorbed through the insect’s alimentary tract and are applied before
an insect feeds. Most of the stomach poisons are inorganic chemicals and familiar
examples are the arsenicals and sodium fluorosilicate.
2. Contact poisons
These kill by direct contact with some part of the insect’s body.
(a) The contact may be made by direct application of sprays, dusts, or aerosols.
An example of this type is parathion.
(b) The pesticide may be applied to a surface on which the insect passes (residual
treatment). The chlorinated hydrocarbon compounds are insecticides of
this type.
(c) The pesticide may be applied in a closed space as a fumigant. Among these
are hydrogen cyanide, methyl bromide, paradichlorobenzene, phosphine,
sulfuro chloride, and carbon dioxide.
3. Systemic poisons
These compounds are taken up by the plant or animal at the point of application whereby they are transported to another part of the body. Some of the
organophosphorus insecticides are systemic poisons.
Most of the organic pesticides act as nerve poisons of the pest in question. They
induce continuous nerve action through inhibition of cholinesterase, producing
tremors, convulsions, and, eventually, death. Since the biochemistry of pest insects
is no different from that of beneficial insects (e.g., honeybee or preying mantis), and
very similar to that of higher animals, including humans, these chemicals must be
used very cautiously.
In contrast to the nerve-poisoning role of nerve poisons, the chlorinated hydrocarbon insecticides interfere with the organism’s production of enzymes, resulting in
a variety of abnormalities such as the thinning of eggshells and subsequent unsuccessful development to maturity, and the elevation and depression of hormone
levels, producing erratic behavior.
While an important and active area of research, this chapter will only include a
very brief discussion on human health risk assessment of acute or chronic effects
chemical pesticide (Sect. 9), as is largely beyond the scope of this work.
5 Pesticide Control of Organisms Pathogenic to Humans
Organisms that are pathogenic for human health widely vary, and are a critical drain
on human productivity and well-being worldwide.
396
L. S. Clesceri and E. J. Clesceri