3 Environmental Control of Pests
Environmental control, via nonchemical means, includes targeted alterations or
control of the natural and man-made environment in which the pest occurs. These
control measures are a necessary precursor to the application of chemical pesticides,
as environmental manipulative methods require an entomological understanding of
the pest life cycle and habitat. It is not advised to apply any chemical control
measures without first establishing an understanding of the pest. This type of
environmental control approach has a wide range of methods that are used in concert
with chemical poisons and is considered Integrated Pest Management or “IPM.”
Indeed, the practice of good hygiene and manipulation of pest habitats can obviate
the need for chemical applications under well-managed systems. A longer term view
of production and pest prevention is favored over the short-term, reactive view.
A good definition of IPM from University of California (UC)-Davis includes:
“Integrated pest management (IPM) is an ecosystem-based strategy that focuses on
long-term prevention of pests or their damage through a combination of techniques
such as biological control, habitat manipulation, modification of cultural practices,
and use of resistant varieties. Pesticides are used only after monitoring indicates they
are needed according to established guidelines, and treatments are made with the
goal of removing only the target organism. Pest control materials [pesticides] are
selected and applied in a manner that minimizes risks to human health, beneficial and
non-target organisms, and the environment.”
There is no general prescription that can apply to every situation regarding the
need for pest control. There are, however, some general rules that can be applied as
outlined in a study of pest control strategies made under the aegis of the National
Research Council [2]. The approach of Integrated Pest Management is applicable to
most situations and includes some of the following principles:
• Practice prevention first, by managing crops or households to prevent pest
problems before they occur.
• Monitor and identify pests. Not all insects, weeds, and wild animals around the
farm are harmful; some may even help.
• Set an action threshold—the point where a pest problem must be dealt with.
Sighting a single pest may not justify a campaign.
• Learn to tolerate a certain level of the pest since most pests are very adaptable to
host, environment, and the control scheme, making them very difficult to eradicate completely.
• Take direct action against pests by suppressing reproduction.
• Enhance the destruction of pests by drawing them to natural predators or making
them susceptible to parasites.
While environmental control through prevention is the recommended first
approach to pest management, as an alternative to the use of chemical poisons,
nonchemical means do not, by in large, provide the immediate response produced by
chemical control. They are, nonetheless, much more desirable as means for pest
390
L. S. Clesceri and E. J. Clesceri
Environmental control, via nonchemical means, includes targeted alterations or
control of the natural and man-made environment in which the pest occurs. These
control measures are a necessary precursor to the application of chemical pesticides,
as environmental manipulative methods require an entomological understanding of
the pest life cycle and habitat. It is not advised to apply any chemical control
measures without first establishing an understanding of the pest. This type of
environmental control approach has a wide range of methods that are used in concert
with chemical poisons and is considered Integrated Pest Management or “IPM.”
Indeed, the practice of good hygiene and manipulation of pest habitats can obviate
the need for chemical applications under well-managed systems. A longer term view
of production and pest prevention is favored over the short-term, reactive view.
A good definition of IPM from University of California (UC)-Davis includes:
“Integrated pest management (IPM) is an ecosystem-based strategy that focuses on
long-term prevention of pests or their damage through a combination of techniques
such as biological control, habitat manipulation, modification of cultural practices,
and use of resistant varieties. Pesticides are used only after monitoring indicates they
are needed according to established guidelines, and treatments are made with the
goal of removing only the target organism. Pest control materials [pesticides] are
selected and applied in a manner that minimizes risks to human health, beneficial and
non-target organisms, and the environment.”
There is no general prescription that can apply to every situation regarding the
need for pest control. There are, however, some general rules that can be applied as
outlined in a study of pest control strategies made under the aegis of the National
Research Council [2]. The approach of Integrated Pest Management is applicable to
most situations and includes some of the following principles:
• Practice prevention first, by managing crops or households to prevent pest
problems before they occur.
• Monitor and identify pests. Not all insects, weeds, and wild animals around the
farm are harmful; some may even help.
• Set an action threshold—the point where a pest problem must be dealt with.
Sighting a single pest may not justify a campaign.
• Learn to tolerate a certain level of the pest since most pests are very adaptable to
host, environment, and the control scheme, making them very difficult to eradicate completely.
• Take direct action against pests by suppressing reproduction.
• Enhance the destruction of pests by drawing them to natural predators or making
them susceptible to parasites.
While environmental control through prevention is the recommended first
approach to pest management, as an alternative to the use of chemical poisons,
nonchemical means do not, by in large, provide the immediate response produced by
chemical control. They are, nonetheless, much more desirable as means for pest
390
L. S. Clesceri and E. J. Clesceri