Bio-Pesticides and Bio-Control Agents in Microbiology
Bio-pesticides & Bio Control
Agents
S. Y. B. Sc. Microbiology
Bacteria can infect human beings, animals
and plants
They are pathogenic but sometimes this
ability to infect is a boon
There are some organisms that are
pathogenic to insects, pests and kill a wide
variety of insects and can be used as Bio
Control Agents
Pseudomonas
as insecticide
Pseudomonas aeruginosa
is among the most
frequently described pathogen causing
disease in insects
Pseudomonas cepacia
is the most versatile
bacteria of soil
A human pathogen a plant pathogen and also
antagonist to plant pathogens through
production of antibiotic
Pyrrolinitrin.
They inhibits root pathogenic fungi
Rhizoctonia solani, Pythium
spp on seed
treatment.
It is a Gram negative bacteria also known to
produce siderophores
Also acts as plant growth promoting
rhizobacteria (PGPR)
They colonize roots to produce antibiotics
against plant pathogens or siderophores
They have adverse effects on the growth of
pathogens. Siderophores chelate Fe
++
and
make Fe
+++
unavailable for growth of other
bacteria.
They are iron chelating low molecular
weight compounds
Pseudomonas fluorescence
One of the most important BCA
They are common PGPR and produce
siderophores
It produces fluorescent siderophores
called
Pyoverdine
or
Pseudobactrin
Low mol. Wt. water soluble, high affinity
Fe
3+
chelators and inhibit pathogens by
creating iron deficient conditions
Inhibit
Rhizoctonia solani, Pythium
spps,
Fusarium
spps on cotton seed treatment
Bacillus thuringensis
Widely known as Bt.
Produces
α
-exotoxin,
β
-exotoxin
δ
-endotoxin (Parasporal body)
Reported to kill insects like moths, beetle,
flies, aphids, insects, ants, termites, midgets,
butterflies and some pathogenic fungi.
Some of the Bt. Strains are pathogenic to
cockroaches, snails and protozoa.
Produces exo and endo toxin hence has
tremendous significance in agriculture
Used as insecticide against almost 100
Lepidoptera & Diaptera
spps
Bacillus thuringensis
is a crystalliferous
bacteria.
They have a crystalline parasporal body
that accompanies sporulation.
On ingestion of Bt. The high pH and
reducing agents in the gut of the insect
dissolve the toxic crystalline protein.
The gut is damaged and becomes non
functional
The feeding ceases almost immediately
The insect dies within 24 to 48 hrs.
Protein does not dissolve in warm blooded
animals hence non toxic to them
After the harvest of Bt. at the end of
fermentation the vegetative cells and spores
are mixed with
bentonite
or other material
as carrier. It is applied as water spray.
Submerged fermentation of Bt.
Working culture slant
Broth culture 500 ml
6 lit small fermentor
500 gallon that is 2000 lit. fermentor for
inoculum preparation
Production tank or bioreactor
Medium of seed fermentor contains beet
molasses1%, corn steep solids 0.85%,
Calcium carbonate 0.1%
Production medium contains beet
molasses 1.86%, corn steep solids 1.7%
cotton seed flour 1.4% and calcium
carbonate 0.1%
A spore count of 2-5
×10
9
spores/ml is
attained within 28-32 hrs.
Viral Insecticides
Viruses and their products are commercially
exploited in place of chemical insecticide
Viruses of the family Baculoviridae are
pathogenic to arthropods.
Viruses contain lipid envelope with circular
double stranded DNA genome of 80-150 kb
pairs
They do not infect vertebrates, non
arthropod species.
Naked DNA of these viruses is infectious.
Bacteria can infect various organisms, and some can be beneficial as bio-control agents against pests. Pseudomonas species and Bacillus thuringiensis are commonly used as bio-pesticides due to their abilities to inhibit pathogens and control insect populations effectively in agriculture.
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Presentation Transcript
Bio-pesticides & Bio Control Agents S. Y. B. Sc. Microbiology
Bacteria can infect human beings, animals and plants They are pathogenic but sometimes this ability to infect is a boon There are some organisms that are pathogenic to insects, pests and kill a wide variety of insects and can be used as Bio Control Agents
Pseudomonas as insecticide Pseudomonas aeruginosa is among the most frequently described pathogen causing disease in insects Pseudomonas cepacia is the most versatile bacteria of soil A human pathogen a plant pathogen and also antagonist to plant pathogens through production of antibiotic Pyrrolinitrin. They inhibits root pathogenic fungi Rhizoctonia solani, Pythium spp on seed treatment.
It is a Gram negative bacteria also known to produce siderophores Also acts as plant growth promoting rhizobacteria (PGPR) They colonize roots to produce antibiotics against plant pathogens or siderophores They have adverse effects on the growth of pathogens. Siderophores chelate Fe++and make Fe+++unavailable for growth of other bacteria. They are iron chelating low molecular weight compounds
Pseudomonas fluorescence One of the most important BCA They are common PGPR and produce siderophores It produces fluorescent siderophores called Pyoverdine or Pseudobactrin Low mol. Wt. water soluble, high affinity Fe3+ chelators and inhibit pathogens by creating iron deficient conditions Inhibit Rhizoctonia solani, Pythium spps, Fusarium spps on cotton seed treatment
Bacillus thuringensis Widely known as Bt. Produces -exotoxin, -exotoxin -endotoxin (Parasporal body) Reported to kill insects like moths, beetle, flies, aphids, insects, ants, termites, midgets, butterflies and some pathogenic fungi. Some of the Bt. Strains are pathogenic to cockroaches, snails and protozoa. Produces exo and endo toxin hence has tremendous significance in agriculture
Used as insecticide against almost 100 Lepidoptera & Diaptera spps Bacillus thuringensis is a crystalliferous bacteria. They have a crystalline parasporal body that accompanies sporulation. On ingestion of Bt. The high pH and reducing agents in the gut of the insect dissolve the toxic crystalline protein.
The gut is damaged and becomes non functional The feeding ceases almost immediately The insect dies within 24 to 48 hrs. Protein does not dissolve in warm blooded animals hence non toxic to them After the harvest of Bt. at the end of fermentation the vegetative cells and spores are mixed with bentonite or other material as carrier. It is applied as water spray.
Submerged fermentation of Bt. Working culture slant Broth culture 500 ml 6 lit small fermentor 500 gallon that is 2000 lit. fermentor for inoculum preparation Production tank or bioreactor Medium of seed fermentor contains beet molasses1%, corn steep solids 0.85%, Calcium carbonate 0.1%
Production medium contains beet molasses 1.86%, corn steep solids 1.7% cotton seed flour 1.4% and calcium carbonate 0.1% A spore count of 2-5 109 spores/ml is attained within 28-32 hrs.
Viral Insecticides Viruses and their products are commercially exploited in place of chemical insecticide Viruses of the family Baculoviridae are pathogenic to arthropods. Viruses contain lipid envelope with circular double stranded DNA genome of 80-150 kb pairs They do not infect vertebrates, non arthropod species. Naked DNA of these viruses is infectious.
