ZARREENA SIDDIQUI
MSc. III SEM
2015 MBM-07
D/OAGRICULTURAL
MICROBIOLOGY

 Term biological pest control first used by Harry
Scott Smith at the 1919 meeting of the
American association of economic
entomologists at California
 The first report of the use of an insect sp.To
control an insect pest comes from Nan Fang Cao
Mu Zhuang (Plants of the southern region) by Ji
han (Botanist).

 Biological control started to emerge in 1870
in U.S.A.
 First international shipment of an insect as
an biological control agent was made by
CharlesV Riley in 1873. Shipping to France
the predatory mites to help fight grape vine
disease agent Phylloxera
 The first importation of the parasitoid into U.S.
was of Cotesia glomerata imported from Europe
to control cabbage white butterfly.

 Relies on predation,
parasitism and other
natural mechanisms.
There are three basic
strategies :
1. IMPORTATION
2. AUGMENTATION
3. CONSERVATION

Importation: classical biological control involves the
introduction of pests natural enemy to a new location where
they do not occur naturally .
o One of the earliest success in west was in controlling Icerya
purchasi(cottony cushion scale) in Australia using a predatory
insect Rodolia cardinalis (vadalia beetle).
o Parasitoidal waspsTrichogramma ostriniae to control
European corn borer Ostrinia nubilalis.

Augmentation: Involves the supplemental release
of natural enemies , boosting the naturally occurring
population .
o All activities designed to increase numbers or effect
of existing natural enemies, achieved by releasing
additional numbers of a natural enemy into a
system or modifying the environment in such a way
as to promote greater number or effectiveness.

 PERIODIC RELEASES OF AUGMENTATION
• Inoculative release: small numbers of the control agents are released
at intervals to allow them to reproduce in the hope of setting up longer
term control and thus keeping the pest down to a low level ; constituting
prevention rather than cure.
• Examples : inoculative release in green house production of several crops
;periodic releases of the parasitoid Encarsia formosa are used to control
green house white fly while predatory mites Phytosieulus persimilis used
for control of spotted spider mite .
• Inundative release: involves mass culture and release of natural
enemies to suppress the pest population directly .
• Example : massive release of Trichogramma sp. in vegetable or field crops
and release rates ranges from 5000- 200000 per acre per week according
to level of pest infestation .

 Conservation: Involves avoidance of measures that destroy
natural enemies and the use of measure that increase their
longevity and reproduction of the natural enemies in an
environment .
o Natural enemies are already adapted to the habitat and to the
target pest and their conservation can be simple and cost effective
.
Conservation involves :
 Avoidance of harmful cultural practices.
 Maintenance of diversity
 Habitat manipulation practice ,providing suitable habitat such as
shelters , natural food , artificial food supplements to increase the
population of natural enemies.
 Protection from pesticides.

 PREDATORS
 PARASITOIDS
 PATHOGENIC
MICROORGANISMS
• Bacteria
• Fungi
• Nematodes
• Protozoa
• Viruses

 PREDATORS: are mainly free
living species that directly consume
a large number of prey during their
whole life time .
Example: Lady bugs particularly their
larvae which are active between
May and July are predators of
Aphids and also consume mites,
sacle insects. Spotted lady beetle
Coleomegilla maculata feed on
eggs and larvae of the colorado
potato beetle Leptinotarsa
decimlineata

 Parasitiods: lay their eggs on or in the body of an insect host which is
then used as a food for developing larvae.The host is ultimately killed ,
most insect parasitoids areWasps .
 Important groups are:
• Ichneumonid wasps :which prey mainly on caterpillars of butterflies.
• Brachonid wasps: which attack caterpillar and wide range of other insects
including green fly.
• Chalcid wasps: which parasitises eggs and larvae of green fly , white fly ,
cabbage caterpillars and scale insects.
• Tachanid fly: which parasitise a wide range of insects including caterpillars,
adult, larval beetles and true bugs.

 Bacteria : used for biological control infects insects via
their digestive tract so they offer only limited options for
controlling insects with sucking mouth parts such as aphids
and scale insects .
• Examples : Bacillus thuringiensis is most widely applied
species of bacteria used for biological control and it can be
used against Lepidoptera , Coleoptera, Diptera.
• Bacillus Popilliae causes Milky spore of the white grubs of
Japanese beetle .
• Bacillus sphaericus used against Diptera .

 Gram positive TARGET INSECTS FOR BtTOXIN
 Aerobic
 Sporogenous
 Rod shaped
 Entomopathogenic
Lepidoptera Diptera
Coleoptera Hymenoptera Nematodes

SPORE
CRYSTALS
‘CRYSTAL’
Crystals made up of 1 or more Cry proteins
Bacillus thuringiensis
spore and cry
protein(toxin)

solubilization In gut lumen, activation of
protoxin to 3-d toxin
to the cadherin receptor
Common to both
models
Pore forming
Cleavage of α-
helix
Oligomerized toxin binds to
glycosylphosphatidylinositol
(GPI) anchored receptors
Activation of Mg2+-dependent signal
transduction pathway leading to cell
death (oncosis)
Stimulation of heterotrimeric G protein
and adenyl cyclase
Increase in levels of cAMP
cAMP activates protein kinase A
Cellular alteration like cytoskeletal
rearrangement and ion fluxing
Alteration in cell chemistry and cell
death
Signal transduction

 Fungi : used successfully to protect crops from a variety of pests.
• They can infect a wide range of insect hosts.
• There has been only limited success in Fungi as biological control agent
because Fungi are slow to kill their host.Whereas some Fungi have a
broad host range .
• Examples: Beauveria bassiana is mass produced and used to manage a
wide variety of insect pests including:White flies,Thripes,Aphids,
Weevils.
• Metarhizium anisopliae produce toxin destruxins used against Beetls ,
Locusts, and grasshoppers.
• Trichoderma viride used against silver leaf disease of stone fruits caused
by Chondrostereum perpureium .
• Verticillium lecanii used for control of aphids and white flies.
• Lagenidium giganteum aquatic fungi used against mosquito larvae.
• Aschersonia aleyrodis used against scale insects and white flies.
• Cordyceps sp. Against arthropods.

 Nematodes: Resides in soil , soft bodied , non segmented,
obligate or facultative parasite on broad range of insects. Introduces new
and environmental- friendly way to eliminate plant pest.
• These harbors gut bacteria which helps in pathogenesis ; symbiotic
association with bacteria.
• Examples:NEMATODES BACTERIA
Steinernema carpocapsae Xenorhabdus nemadophilus
Steinernema affinis Xenorhabdus bovienii
Steinernema glaseri Xenorhabdus pionarii
Heterorhabdus bacteriophora Photorhabdus leuminiscense
Heterorhabdus megidis Photorhabdus leuminiscense
Heterorhabdus zealandica Photorhabdus leuminiscense

 When Heterorhabdus attacks insect larva it turns red.
 When Steinernema attacks insect larva it turns brown .

Examples:

 Viruses:are obligate disease causing organisms that can
reproduce within a host insect.
• They can provide safe , effective and sustainable control of a
variety insect pests usually attack larvae of lepidoptera or
hymenoptera.
• Viruses are host specific .Virus induced mortality is caused
by toxic proteins that accumulate during reproductive cycle
of virus after death of insect the integument and internal
tissues melt away.

• Bculoviruses are arthropod specific group :
• Two genera :
I. Nuclear polyhedrovirus(multiple virions occluded in polyhedra).
After Infection larvae initially white then darken.
I. Granulovirus(single virion occluded in granules). After infection
larvae turns milky white and stop feeding.
Examples: Lymantria dispar used against larvae of Gypsi moth .
U.S. forest service has used NPVs as biological control agents for Pine
saw flies,Tussock moths.

• Baculovirus is sprayed onto foliage –> Caterpillar consumes the virus –>The protein
encapsulating the Baculovirus DNA dissolves and the DNA enters the stomach cells –
> Baculovirus DNA is replicated by the stomach cells until the stomach cells rupture –>The
caterpillar stops eating –> Baculovirus is spread throughout the caterpillar causing a
general systemic infection –>The caterpillar dies within day

 Upadhyay,R.K., Mukherji,K.G., and Rajak,R.L. IPM system in
agriculture.
 De Bach, P. Biological control of insect pests and weeds,
Chapan and Hall, New yYork.
 Burges,H.D. and Hussey,N.W. Microbial control of insect and
mites.
 Saxena, A. B. Biological control of insect pest.
 Wikipedia.

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