BIO-PESTICIDES
Sarabjeet kaur
Bsc. Agri (hons.), DAV University, Jalandhar,
Punjab, India
Abstract
Biopesticides are biochemical pesticides that
are naturally occurring substances which control pests by nontoxic mechanism. Biopesticide is a
mass-produced, biologically based agent manufactured from a living
microorganism or a natural product and which is sold for the control of plant pests
;(1). The market share of biopesticide in India is only 2.5% of total pesticide
market.
INTRODUCTION
It
is already reported that chemical fertilizers and chemical pesticides have
tremendous harmful long - term residual effect not only on the soil - health
and crop-productivity but also they contaminate the ground water level and
ultimately they are incorporated into the food chain in the ecosystem causing
human health hazards. Previously, we have reported that 'Furadan' and
'Malathion' pesticides caused teratogenic effects both in the adult and
embroyonic stages including birds (as animal model) at the histomorphological,
genetical and biochemical levels(2). Some pesticides and related chemicals are
persistent in the environment and are accumulated in the fatty tissues of
organisms and increase in concentration as thethey move up through the food-web.
These chemicals which show bio magnification, after bio accumulation, are
substances that can cause effects by interfering in someway with the body's
hormones or chemical messenger. A recent study indicated that atrazine effected
the sexual diseases and development of frogs, even at extremely low doses.
Unlike chemical pesticides and fertilizers, bio-pesticides and bio-fertilizers
contain viable population of the selected microbes which may be colonized in
the soil ecosystem. Pest control by biological agents appears to be very
'useful tool' in recent years. Though there are a few reports that
bio-pesticides are now being introduced into the agricultural fields but
unfortunately not absolutely as bio-fertilizer or pesticides but mixing with a
little amount of chemical pesticides for enhancing their effectiveness.
TYPES OF BIO-PESTICIDES
There are mainly three types of bio-pesticides:-
1. Microbial bio-pesticides
2. Plant-Incorporated-protectants (PIPs)
3. Biochemical bio-pesticides
1. Microbial biopesticides: Microbial pesticides
contain micro-organisms viz. bacterium, fungus, virus, protozoan or algae
(alga) as active ingredient. Microbial pesticides can control many different
kinds of pest, although each separate active ingredient is relatively specific
for its target pest. The most widely known microbial biopesticides are Bacillus
thuringiensis or (b.t).They produce little or no toxic
residue, and development and registration costs are significantly lower than
those of synthetic chemical pesticides (Hajek, 2004).They can be applied to
crops using the same equipment used to apply chemical pesticides, formulated in
similar ways to pesticides to enhance their efficacy, and they tend to have
very short harvest intervals.
2.Plant-Incorporated-protectants (PIPs): PIPs are pesticidal substances
that plants produce from genetic material that has been added to the plant.Plant-incorporated protectants are pesticidal substances produced by
plants and the genetic material necessary for the plant to produce the
substance. For example, scientists can take the gene for a specific Bt
pesticidal protein and introduce the gene into the plant's genetic material.
Then the plant manufactures the pesticidal protein that controls the pest when
it feeds on the plant ;(3). Both the protein and its genetic material are
regulated by EPA; the plant itself is not regulated ;(3).
3. Biochemical bio-pesticides: Biochemical
biopesticides are naturally occurring compounds or synthetically derived
compounds that are structurally similar to their naturally occurring
counterparts.
Biochemical bio-pesticides are divided into
different subcategories as:
Plant
Growth Regulators
Plant Growth
Regulators (PGRs) include a category of both natural and manufactured versions
of natural substances that affect major physiological functions of plants. PGRs
can promote, inhibit, or modify the physiological traits of a range of fruit,
vegetable, ornamental and agronomic crops.
Under each
class there are a number of PGR products that play specific and very important
roles in optimizing crop yield and quality.
·
Gibberellins
play a role in cell elongation, stem growth, bolting in long-day plants,
induction of seed germination, enzyme production during germination, fruit
setting and growth, and induction of maleness in dioeciously flowers.
·
Cytokines are involved in growth promotion
through cell division, fruit abscission, growth of lateral buds, leaf
expansion, delay of leaf senescence, enhancement of stomatal opening, and
chloroplast development.
·
Abscisic acid can influence water relations via
stomatal closure, inhibit shoot growth, inhibit alpha-amylase synthesis in
seeds affecting dormancy, increase fruit coloring, and promote leaf and fruit
abscission.
·
Ethylene
can stimulate lateral growth in stems, stimulate defense responses to injury,
break dormancy, abscise leaves, flowers and fruit, induce flowering, and
stimulate fruit ripening.(4)
·
Auxins
can promote growth through cell enlargement, release apical dominance, and
influence rooting, leaf senescence, flowering, fruit set and growth, fruit
ripening, and leaf and fruit abscission.
Conclusion: Due to "chemical
pesticide" problems in India, there is an urgent need to promote
environmental friendly 'Biopesticides' in the country. Moreover, recent Government
policies also favor "Biopesticides and Biofertilizer”.Application of
Biofertilizers and biopesticides has thus become an integral component of
nutrient management system. Apart from these, they play a vital role in
increasing the agricultural production, a need of the day.
References:
2. Subrata Datta Department of
Zoology, East Calcutta Girl’s College Lake Town, Kolkata, INDIA. E - mail : subrata_0202@yahoo.com
3.
United States Environmental
Protection Agency
4. bpio. Biopesticide industry alliance
http://www.bpia.org/biochemical-biopesticides/
BIO-PESTICIDES and Their Types
![BIO-PESTICIDES and Their Types]()
Reviewed by Sarab Thind
on
October 23, 2017
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