Page 527 - Biosystems Engineering

Agricultur e Management 499

17.2.6 Biological Control
Chemical pesticides produce harmful effects to the environment as
well as to human and animal health. Safer alternative methods to
control these pests are urgently required by biological control as well
as suppressing the insect population by the action of their native or
23
introduced natural enemies.
Integrated pest management is important for environmental safety
(Fig. 17.5). This process involves the selection, integration, and imple-
mentation of pest control based on predicted economic, ecological,
and sociological consequences. It is based on different physical,
chemical, biological, and mechanical control, use of pesticide at the
most susceptible stage of the pest, use of resistant varieties, mixed
cropping, and crop rotation.
In the United States, integrated pest management (IPM) was for-
mulated into national policy in February 1972 by President Richard
Nixon. In 1979, President Jimmy Carter established an interagency
IPM Coordinating Committee to ensure development and implemen-
tation of IPM practices.

Biopesticides
Biopesticides are made by directly using the biological organism as
microbial pesticides or by using organismal products as biochemical
pesticides or as plant-incorporated protectants. Based on the target
organism, microbial pesticides can be broadly classified as follows.

Bioinsecticides Biopesticides should completely control the specific
target and be biodegradable and cost effective. Bioinsecticides are
based on mutant strains of the bacterium Bacillus thuringiensis (B.t.),
the most widely used and successful microbial pesticide. There have
been over 30 subspecies of B.t. classified, containing over 140
described crystalline toxins. These toxins have not only shown activ-
ity against lepidoptera, diptera, and coleoptera, but recent isolates

Use of biopesticide
Replacement of chemical pesticide

Decreased of environmental pollution

Lesser health risk and increase in beneficial organism

Protection of natural resources

Healthier environment
FIGURE 17.5 Gradual replacement of chemical pesticides for environmental
safety.