Microbial pesticide.Microbial pesticides consist of a microorganism (e.g., a bacterium, fungus, virus or protozoan) as the active ingredient.

Naturally occurring or genetically modified microorganisms that are used as a safe alternative to chemical pesticides.

1. Microbial Pesticide
Bio pesticides are types of chemicals extracted from natural materials such as plants, animals,
bacteria or certain minerals and these chemicals can be used for controlling pests. For example,
canola oil/baking soda with pesticidal applications are considered bio pesticides. Bio pesticides
are pesticides based on specific micro-organisms used to control pests, diseases and weeds.

Classification:
All the bio-pesticides can be put into following three classes depending upon their source of
origin:
1) Microbial Pesticides: this consists of microorganisms like a bacterium, fungus, virus or
protozoan as an active ingredient. These can control many different kinds of pests, although
each separate active ingredient is relatively specific for its target pest[s]. For example, there are
fungi that control certain weeds and other fungi that kill specific insects.
2) Plant-Incorporated-Protectants: These are the substances having pesticidal actions
produced by genetic material of the plants or bacteria. For example, pesticidal protein of the Bt.
Gene bacteria can be introduced into the plant's genetic makeup. The BT gene infused plant
starts manufacturing the pesticidal substance. In the event of any specific pest attack on the
plant, the attacking pest is killed by the pesticidal action of the protein.
3) Biochemical Pesticides: These are naturally occurring substances. They exert pesticidal
properties by non-toxic mechanisms, similar to that of allelo-chemicals. Conventional

2. pesticides are synthetic materials that directly kill or inactivate the pest. Biochemical pesticides
include substances, such as insect sex pheromones, and various other scented plant extracts that
attract insect pests to traps.
Bacterial Bio pesticide:
Bacteria are single celled microorganisms without a defined nucleus. They are extremely
variable; some produce cells that occur singularly while others occur in chains or packets. Some
species are motile (moving) while others are non-mobile. Some require oxygen, while others
develop best in an anaerobic (without oxygen) environment. Bacterial pathogens of insects can
be divided into two broad categories: spore forming and non-spore forming bacteria. Most
of the species of bacteria isolated from diseased insects are non-spore and spore forming
bacteria. They belong to the genus Bacillus and are important from the biological control angle.
The spore formation is the character of bacteria to escape the non-congenial environment by
forming a spore
Non-spore forming bacteria:
These bacteria have a low disease causing capability (pathogenicity) when they occur in the
digestive tract of an insect, but may be highly pathogenic if they are able to enter haemocoel
(blood) of insects. Thus, the diseases caused by non-spore forming bacteria generally rely on a
conditional factor to gain entrance into the haemocoel. The general term 'stress' encompasses
many of these conditions. Non-spore forming bacteria which are not active invaders may enter
the haemocoel when the insect has been stressed or injured. Once these bacteria are inside the
insect, they multiply rapidly and cause the death of the insect. For instance, Serratia marscens
is the non-spore forming bacteria, which are effective against insects belonging to moths and
butterflies (Lepidoptera) like Helicoverpa armigera and Spodoptera litura.

Spore forming bacteria:
Spore- forming bacteria produce environmentally resistant spores in addition to vegetative or
reproductive cells. There are three primary genera; Bacillus is generally aerobic (require
oxygen) and the genus Clostridium is anaerobic. The genus Bacillus contains both species that
produce toxins and species that do not produce toxins. The other spore forming bacteria, which
are commercially produced, are Paenibacillus papillae for control of Japanese beetles and
Bacillus sphaericus for mosquito control.
The details of the important species of Bacillus spp. are as follows

3. Bacillus thuringiensis:
This bacterium produces proteinaceous substances during sporulation, which is bipyramid in
shape with a thick walled endospore. It is an endotoxin, which dissolves inside the host in
alkaline gut fluids and releases toxic polypeptides. This particular species acts mainly against
lepidopterans, but some of the strains specific to mosquitoes and Coleoptera (beetle) are also
available. This is being extensively used throughout the world.
Bacillus thuringiensis acts as stomach poison. The infection occurs through ingestion. The
bacterium develops in the intestinal tract of its host and later passes on to the haemocoel and
finally killing the insect.
Bacillus thuringiensis (Bt) is widely used as a microbial insecticide commercially produced. It
is very effective on insect groups like moths and butterflies (BT kurstaki and Bt aizawai),
beetles (Bt tenebrionis and Bt japonensis) and flies (Bt israeliensis). The activity of Bt is due to
the presence of a variety of toxins that they produce. Normally in field conditions, one kilogram
of Bt is made into a thick paste by adding small quantity of water. It is mixed in 200-300 litres
of water to be sprayed in one acre.

4. Bacillus papillae:
This particular species produces no toxins. Japanese beetle I (Popillia japonica) larvae ingest
spores from the soil which germinate and 21 days after initial infection, the insect body gets
swollen and becomes creamy white (milky disease). After death, the spores are released into the
soil and establish as persistent infection sites

Fungal microbial pesticide:
Fungi are another group of microorganisms, which are widely used as bio pesticide. There are
some 700 species of entomopathogenic fungi from 100 genera, but only 10 species are utilized
for insect control. Most of fungi access to host insect through their body cuticle. After accessing
the germination 1 of spores, a number of biochemical developments occur in the fungus and
insect between the growth and reproduction stages. The Deuteromycetes fungi are the easiest to
produce in vitro and have a wide range of host infestation. The most important fungi, which are
commercially used, are Beauveria sp., Metarrhizium sp. and Verticillium sp.
Beauveria bassiana
Beauveria bassiana is a common fungus found in the soil. It attacks a wide range of both
immature and adult insects like whiteflies, aphids, grasshoppers, termites, weevils, etc.
Beauveria produces spores that are resistant to environmental extremes. The spores infect
directly through the outer surface of the insect skin. Under favourable temperature and moisture
conditions, the spore adhering to the insect or host will germinate and secretes enzymes, which
attack and dissolve the cuticle (outer layer of the insect body). It then enters into the insect body
and multiplies. In the insect body, it produces a mycotoxin that weakens the immune system of
the host. Beauveria is available commercially as a microbial insecticide because it can be easily
mass-produced by fermentation process.
Metarrhizium anisopliae
Metarrhizium anisopliae is another fungus which is widely used in organic agriculture. This is
also called Green Muscardine Fungus. It is highly active on white grubs, beetles, caterpillars,
semiloopers, cutworms, aphids, mealybugs etc. It infects all stages of the insects like eggs,
larvae, pupae, nymphs and adults. The spores of these fungi enter the insect body and kill the
insect. It can also be applied in the soil wherein 200 ml (liquid formulation) or 1 kilogram
(powder formulation) can ‘be mixed in 50-100 kgs of farm yard manure (FYM) or 2-3 month
old cattle manure which is sufficient for one acre. This fungus can also be applied as foliar
spray

5. Verticillium lecanii
Verticillium lecanii is available in the powder and liquid formulations. This fungus is very
effective on insects which suck the plant sap (sucking type of insects) like scale insects, aphids,
thrips, jassids etc., on a variety of crops. It attacks all the stages of insect and the mode of action
is similar to the above mentioned fungi. It is sprayed at the rate of 5 ml in one litre of water.
Addition of jaggary and soap solution to the spray before spraying on the standing crop
improves the results
VIRAL BIOPESTICIDE
Like bacteria and fungi, viruses are also utilized in managing the pests. The most important
group of viruses used as a bio-pesticide is called as Nuclear Polyhedrosis Viruses (NPV). These
viruses are known to infect over 500 species of insects. When the larvae of insects ingest these
viruses, the larval body gets darkened, tissues disintegrate and finally it dies.
Baculoviruses: Nuclear Polyhedrosis Viruses (NPV)
Description: About 280 members of this species are known. It is rounded cubic or hexagonal
polyhedral in shape and 0.5-1.5 microns (pm) in size. It is having single envelop and sometimes
multiple envelop.
Infection: Infection occurs in the adipose tissue of the hypodermis and also in the tracheae and
the middle intestine.

6. Host: Approximately 120 species of Lepidoptera and Hymenoptera (particularly sawflies). Each
virus is highly specific to its host.
Survival: Nuclear polyhedrosis viruses form particles inside a crystalline protein structure
(occlusion body). This allows the virus to survive outside the host for years out of sunlight.
Biocontrol agents: The NPVs have all been produced on a commercial or semi-commercial
scale: Autographa californica NPV, Lymantria dispar NPV, Malacasoma disstria NPV,
Mamestra brassicae NPV, Neodiprion sewer NPV, Spodoptera NPV and Heliothis NPV.

(A) Baculoviruses has two genera, which are characterized by morphology of occlusion bodies. NPV has multiple virions
in polyhedral form occlusion bodies while GV has single virions in granule form. NPV strains defined as having a single
or multiple nucleocapsid in an envelope.
(B) Infection cycle of Baculoviruses. 1. Baculoviruses are ingested by insect larvae. 2. The occlusion bodies are dissolved
in the alkaline mid-gut and virions infects the host through the mid-gut cells. Virus particles then replicate inside the
insect cells. 3. Virus particles are released to the environment when infected cells were disintegrated.

7. Category Products Target pests Major crops
Bacteria Bacillus thuringiensis
Bacillus sphaericus
Bacillus subtilis
Pseudomonas fluorescens
Moths Mosquitoes,
flies Fungal
pathogens Fungal
pathogens
Cotton, maize,
vegetables, soybean,
groundnut, wheat,
peas, oilseeds, rice.
Fungi Trichodenna viridae
Trichodenna harzianum
Trichodenna hamatum
Fungal pathogens Wheat, rice, pulses,
vegetables,
plantations, spices
and sugarcane.
Beauveria bassiana
Verticillium lecanii
Metarrhizium anisopliae
Paecilomyces lilacinus
Nomuraea rileyi
Insect pests such as
bollworm, white flies,
root grubs, tea
mosquito bugs
Cotton, pulses,
oilseeds, plantation
crops, spices and
vegetables.
Virus Nuclear polyhetirosis Virus
(NPV) of Helicoverpa
annigera, Spodoptera sp, and
Chilo infescatellus
American Boll worm,
tobacco caterpillar
and shoot borer
Cotton, sunflower,
tobacco and
sugarcane

Methods of Application:
The indiscriminate and repeated application of synthetic pesticides has led to persistence and
residual toxicity in the soil and water. Even with such expensive inputs, the diseases and pests
have not come under control. The repeated fungicidal sprays had depleted the beneficial soil
microorganisms and the pathogens. They have also developed resistance. The microorganisms
that are used to manage the plant diseases are Trichoderma, Pseudomonas and Bacillus. These
biocontrol agents can be applied to various plant parts like seed, root, foliage, and also for the
soil.
Seed Treatment
The seeds are treated with the biocontrol agents in a very simple way. Seeds are immersed in
water for one minute and then spread on a polythene sheet. Trichoderma viride at the rate of
10gmkg of pulses, oilseeds and cotton is mixed with the seeds as inoculants and then seeds are
sown in the field. Pseudomonas fluorescens is also used by the farmers to manage diseases like
root and stem rots, damping off, Downey and powdery mildews in different crops. Seed
treatment of Pseudomonas fluorescens at the rate of 10gmkg of seeds can protect the seedlings
from different diseases.

8. 'Soil Application
The biocontrol agents like Trichodemza is very effective when applied in the soil. About five
kg of Trichodemza is mixed with 100 kg of farm yard manure or well rotten cattle manure. It is
moistened with water for one week period and then broadcasted in the soil after ploughing,
before sowing of seeds
Foliar Application
The bio pesticide can also be sprayed on the crop as a foliar spray by using the knapsack
sprayer. One kg of bio pesticide mixed in 200- 250 litres of water can be sprayed on the crop in
one hectare of area.
Seedling Dip
To protect the seedlings from pests and diseases, they can be treated with biopesticide before
planting. About 10 gram of bio-pesticide is mixed in a litre of water and seedlings are dipped in
the solution for about 30 minutes. The treated seedlings are planted in the main field. The bio-
pesticide solution makes a thin layer around the plant roots.
Soil Drenching
This practice is most suitable for plantation crops. It has been observed that certain diseases
appear every year and affect the plants. In this case, the pathogens causing the disease live in
the soil. To inactivate them, the soil around the plant is applied with the bio-pesticide solution.
This process is called as soil drenching. About 10 gm of suitable bio-pesticide is mixed in one
litter of water and applied around the tree in the ring prepared for application of water.
Depending on the size of the ring area around the plant or tree, the quantity of the solution
should be prepared.
Usage in the Nursery Bed
In vegetables and flower crops, the nursery is prepared first and then seedlings are transplanted
in the prepared beds. The seedlings in nursery get infected with a variety of microorganisms
which causes different diseases. In such conditions, the nursery soil should be treated with the
bio-pesticide (inoculation) by mixing it in the soil. The seed is sown after mixing the
inoculation in the soil. It provides protection to the young seedlings from diseases.

9. Advantages
1. They are environmentally safe and cause no pollution to soil, air and water.
2. The beneficial organisms are not affected unlike synthetic chemical pesticides.
3. The bio-pesticides are cheaper than the chemical pesticides.
4. Bio-pesticides do not require repeated application as they multiply themselves.
5. They help in inducing resistance to the crops.
6. They are safe to the farmers who handle them.
7. The approach is bio-rational.
DISADVANTAGES
1. High production costs.
2. Limited availability.
3. Limited awareness among farmers.
4. Requirement of special skill for application.
5. Difficulties in formulation and application.
6. Lack of commercial awareness on the part of manufacturers.
7. Host specific.
8. Culture and quality requires special skill.
9. specific time for application.