Viruses are being explored as potential biopesticides to control insect pests. The major viruses investigated are baculoviruses, which primarily infect lepidopteran insects. Baculoviruses are classified as nucleopolyhedroviruses (NPVs) or granuloviruses (GVs) depending on how their virions are occluded. NPVs occlude virions in large polyhedral bodies, while GVs occlude individual virions. These viruses replicate in the nucleus or cytoplasm of infected insects and cause symptoms like discoloration, lethargy, and death. Large-scale production can be done in vivo by applying the virus to host insects or in vitro by infecting insect

1. VIRAL
BIOPESTICIDES

2. Viruses as Biopesticides
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Lepidoptera( 83%)
Hymenoptera (10%)
Diptera ( 4%)

3. Classification
• Baculoviruses
Nuclear Polyhedrosis Granulosis Virus
Virus
• Nucleic acid-single molecule of circular super
coiled DNA
• Virion structurally complex with 10 -25
polypeptides 4-11 associated with nucleocapsid
• Replication in host cell nuclei
• Cytoplasm Polyhedrosis
Virus

4. Nuclear Polyhedrosis Virus
• 41% of arthropod viruses develop in host cell
nuclei, virions occluded singly/groups in
polyhedral inclusion bodies.
• Rod shaped, double stranded; POBs 0.2-15µm in
diameter
• Highly host specific
• Enters through injection of plant material into
insect gut through mouth &cuticle
• Symptoms are:
- Discoloration (brown and yellow)
-Stress
-Decomposition (liquification)
-Lethargy
-Infected larvae hang invertedly from twigs
- host will become visibly swollen with fluid
containing the virus and will eventually die
turning black with decay

5. Left: A larvae of H. armigera that died of NPV on chickpea plant in India; note
the characteristic hanging stance. Right: A larvae of H. armigera that died of NPV
on cotton plant in India; note the characteristic hanging stance.

8. Granulosis Virus
• Develop either in the nucleus/cytoplasm/
tracheal matrix / epithelial cells of host
• Virions are occluded singly in small inclusion
bodies called capsules
• Rod shaped virion, Ds DNA
• Oval occlusion bodies about 200x400nm
• They enter through ingestion, similar to NPV
• Fat body is the major organ invaded
• Diseased larvae – less
active, flaccid, fragile, wilted prone to rupture in
later stages, death in
6-20 days

9. Western grapeleaf skeletonizer is a pest of grapes that periodically defoliates vineyards

10. Cytoplasm Polyhedrosis Virus
• Develop only in cytoplam of host
midgut epithelial cells
• Virions occluded singly in polyhedral
inclusion bodies, Ds RNA
• Average diameter is 60nm
• POBs range from 0.5-15µm in
diameter
• Infection confined to midgut and
does not spread to other tissues
• Infection not always lethal but shows
larval growth reduction
• Continuosly shed infective polyhedra
in faeces

11. Heterocampa guttivitta larva infected with
cytoplasmic polyhedrosis virus (CPV)

13. Large Scale Production
• In vivo
- applying the virus against the host insect in the field and collecting diseased or dead larvae
-producing the target insect in the laboratory on an artificial diet
• In vitro
- Baculovirus production in insect cell cultures

14. A clonal cell line Spex-II-A and a clonal cell line Hz-AM-1-1
infected with HaNPV, which established in the laboratory

16. Genetic Engineering

17. • Narrow Host Range
• Environmentally Safe, No Risk of Toxicity
• No Adverse Effects on Other Species, Insect
Pollinators remain unharmed

18. Drawbacks
• Chemical Pesticides cause more effective reduction
of insect population and better crop protection
• Viral pesticides require more involved monitoring
system
• The number of application on a particular area is
more than chemical pesticides
• Viral pesticides cannot be stored for longer periods
of incubation
• Producers more comfortable and experienced with
use of chemical pesticides- marketing problems

19. References
• Baculoviruses as biopesticides
-Seema Mishra (Eukaryotic Gene Expression Laboratory, National Institute of
Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India)
• Baculovirus Biopesticides
-Boguslaw Szewczyk*, Marlinda Lobo de Souza, Maria Elita Batista de
Castro, Mauricio Lara Moscardi and Flavio Moscardi (Department of
Molecular Virology, University of Gdansk and Medical University of
Gdansk)
www.biopesticideindustryalliance.org/microbialviruses.php
www.scribd.com/doc/78234955/22/b-3-Viral-Biopesticides
www.sciencedaily.com/releases/2010/08/100820133238.htm