Page 5 - Natural Pesticides PDF Flipbook

Oguh et al.; AJBGE, 2(3): 1-18, 2019; Article no.AJBGE.53356

poisons and pose a long-term danger to the necessary to understand how the pests’ targeted
environment and humans through their systems normally function. It is also helpful to
persistence in nature or body tissue. Most of the understand how human systems function in order
pesticides are non-specific and may kill life forms to know similarities and differences between
that are harmless or useful [12]. Pesticides are humans and the pests we try to control. It is also
classified in three ways generally: Based on very important to understand the modes of action
chemical structures, According to their mode of of the pesticides we use is to prevent the
action and According to their mode of entry i.e. development of pesticide resistance in the target
ingestion, inhalation, contact absorption. pest(s). Using pesticides with same mode of
action contributes to this problem by killing the
1.1.3 Natural pesticides susceptible pests and leaving only those with
resistance to the entire class of pesticides that
Natural pesticides are naturally occurring work through similar mechanisms [15].
chemicals extracted from plants. Natural
pesticide products are available as an alternative 2. SCOPE OF BIOPESTICIDES
to synthetic chemical formulations but they are
not necessarily less toxic to humans. Some Efforts is been made to find biopesticides with
deadly, fast-acting toxins and potent carcinogens novel mechanism of action and have no cross-
occur naturally [13]. resistance with the old pesticides. Biopesticides
are a distinct group of pesticides which is
1.1.4 Pest management different from conventional pesticides. They are
comprised of two major categories, which are the
Pest management is a means of reducing pest biochemical pest control agents (e.g.,
numbers to an acceptable or economical pheromones, hormones, natural plant growth
threshold. While IPM is a developed method or regulators and enzymes) and the microbial pest
ways use to control pests without relying solely control agents (e.g., microorganisms). Pesticides
on pesticides. The IPM is a systematic plan to be included in these categories must be
which brings together different pest control naturally occurring, or if man synthesizes the
tactics into one program. Management does not chemical, and then it must be structurally safe
mean eradicating pest. It means finding tactics and identical to a naturally occurring chemical.
that are effective and economical, and that keep Minor differences between the stereochemical
environmental damage to a minimum level. isomer ratios (found in the naturally occurring
compound compared to the synthetic compound)
1.1.5 Selectivity will normally not rule out a chemical being
classified as a biopesticides unless an isomer is
Selectivity is the use of pesticides to kill pests but found to have significantly different toxicological
not affecting their natural enemies. Or are a type properties from those of another isomer. Thus,
of pesticide that target a specific pest species. the application of active toxic biopesticides
agents as an alternative control strategy results
1.1.6 Mode of action in an urge to look for environment-friendly,
biodegradable and easily available at affordable
The mode of action or mechanism of action of prices products for pests control.
pesticide is how the pesticide works. In other
words, it is how the specific systems in the pest 2.1 Uses of Biopesticides
are affected by the pesticide. Mode of action
refers to the specific biochemical interaction Biopesticides give better control than
through which a pesticide produces its effect on conventional pesticides such as organochlorine,
the pest. Usually, the mode of action includes the biopessticides are usually a narrow spectrum of
specific enzyme, protein, or biological step activity; are cheaper, less toxic to workers or
affected. While most other classifications are the consumers; usually true to type, safer for the
pests controlled, physical characteristics, or environment and for beneficial insects; and
chemical composition, mode of action specifically required for certified organic production
refers to which biological process the pesticide surroundings. Biopesticides may be applied
interrupts [14]. Knowing the mode of action is shortly before harvest without leaving excessive
integral for scientists to improve the quality and residues, are less persistence in the environment
sustainability of a product. To understand how and have reduced risks to non-target organisms.
pesticides work (their mode of action), it is They act very quickly in insect to stop feeding,

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