Microbial insecticides offer an alternative to synthetic chemical insecticides for pest control. They include bacteria like Bacillus thuringiensis (Bt), fungi, viruses, protozoa, nematodes, and actinomycetes. Bt is the most widely used and produces crystal proteins that are toxic once ingested by the target insect. Other common microbial insecticides include Beauveria bassiana, Metarhizium anisopliae, nuclear polyhedrosis viruses, and the actinomycete insecticides avermectins, milbemycins, and spinosad. Microbial insecticides have advantages like being non-toxic to humans and wildlife but also have disadvantages like being pest-

1. Microbial
insecticid
es

2. INTRODUCTION
Insect population is the largest with more than
750000 species
Negative effects of insects
Synthetic chemical insecticides provide many
benefits to food production and also pose some
hazards.
Alternative methods of insect management offer
adequate levels of pest control and pose fewer
hazards.

3. MICROBIAL INSECTICIDES
Single cell organisms, such as bacteria, fungi
and protozoa, and viruses, have been mass
produced and formulated for use in a manner
similar to insecticides.
• Microbial insecticides can be
1. Microbially produced toxic substance
2. Organism
(Weinzieri, R. And T. Henn.

4. TYPES
• BACTERIAL
• ACTINOMYCETES
• VIRAL
• FUNGAL
• PROTOZOAN
• NEMATODES

5. BACTERIAL INSECTICIDES
• Spore forming
• Rod-shaped
• Genus bacillus.
• Isolated from soil samples.
• Stomach poisons.

6. TYPES
• OBLIGATE- B. papillae, B. lentimorbus
• FACULTATIVE- B. cerens, BT
• POTENTIAL- P. aeruginosa

7. HISTORY OF BT
•Discovered in japan in 1901 by Ishiwata
•Officially described by berliner in 1915, isolated from
mediterranean flour moth in province of thuringia in 1911
•US production of a subspecies thuringiensis in late 1950’s
•Discovery of highly active subspecies kurstaki HD-1 by
dulmage, 1960’s, commercial production 1970s
•Discovery of mosquito, black fly active subspecies
israelensis by goldberg and margalit, 1980’s
•Discovery of beetle-active subspecies morrisoni by krieg,
1980’s
•Genetically engineered cotton, corn, potatoes ongoing

8. Bacillus thuringiensis berliner
• gram-positive, aerobic
• parasporal body (known as the crystal) that is
proteinaceous and possesses insecticidal
properties.
• The parasporal body comprises of crystals and
tightly packed with proteins called protoxins or
endotoxins.
• over 60,000 isolates of Bt are being maintained in

11. . Three-dimensional structure of Cyt toxins from Bacillus thuringiensis displayed by
Swiss PDB viewer. Cyt1Aa, pdb 3RON; Cyt2Aa, pdb 1CBY; and Cyt2Ba, pdb
2RCI.
Mario Soberón, Jazmin A. López-Díaz, Alejandra Bravo
Peptides, Volume 41, 2013, 87–9

12. VARIOUS STRAINS OF B. thuringiensis
Strain/subsp. Protein size Target Insects Cry # shape
berliner 130-140 kDa Lepidoptera Cry1 bipyramidal
kurstaki KTP, HD1 130-140 kDa Lepidoptera Cry1 bipyramidal
entomocidus 6.01 130-140 kDa Lepidoptera Cry1 bipyramidal
aizawai 7.29 130-140 kDa Lepidoptera Cry1 Bipyramidal
aizawai IC 1 135 kDa Lepidoptera,
Diptera
Cry2 Cuboidal
kurstaki HD-1 71 kDa Lepidoptera,
Diptera
Cry2 cuboidal
tenebrionis (sd) 66-73 kDa Coleoptera Cry3 flat/irregular
morrisoni PG14 125-145 kDa Diptera Cry4 bipyramidal
israelensis 68 kDa Diptera Cry4 bipyramidal

13. MODE OF ACTION
• THREE STAGE PROCESS
STAGE1
STAGE2
STAGE3

15. B. thuringienis parasporal crystal composed of
Cry1 protoxin protein. Conversion of the 130-kDa
protoxin into an active 68-kDa toxin requires an
alkaline environment (pH 7.5 to 8) and the action
of a specific protease, both of which are found in
the insect gut. The activated toxin binds to
protein receptors on the insect gut epithelial
cells.

16. The toxin is inserted in gut epithelial cell membranes of the
insect and forms an ion channel between the cell cytoplasm
and the external environment, leading to loss of cellular
ATP and insect death.

17. APPLICATION
• Spray when caterpillars are still small.
• Completely cover all leaf surfaces. The insects
must ingest the bacteria when they are feeding.
• Spray in the evening or during cloudy (but not
rainy) days.
• There may be a need to reapply if it rains soon
after application.

18. COMMERCIAL BT PRODUCTS
organism Product name
1.Bacillus thuringiensis
var. kurstaki
Dipel®, Javelin®, Thuricide®,
Worm Attack®, halt
Caterpillar Killer®,
Bactospeine®, and SOK-Bt®
2. B.thuringiensis var.
aizawai
Certan®
3. B. thuringiensis var.
israelensis (Bti)
Vectobac®, Teknar®,
Bactimos®, Skeetal®, and
Mosquito Attack®.
4. Bacillus popillae and
Bacillus lentimorbus.
Doom®, Japidemic®, Grub
Attack®,
5. Bacillus thurigiensis
var. san diego,
M-One®,

19. GLOBAL SHARE OF BT
• USA
• INDIA
• CHINA
• ARGENTINA
• BRAZIL
• S. AFRICA
• CANADA
• PHILIPHINES
• AUSTRALIA
• URUGUAY
Plant Biotechnology Journal ª 2011 Society for Experimental Biology, Association
of Applied Biologists and Blackwell Publishing Ltd, Plant Biotechnology Journal,
9, 283–300

20. ACTINOMYCETES
 Large group of gram positive bacteria that
grow as hyphae like fungi
 Mortality is due to secretion of bioactive
materials which stimulate GABA system or
disruption of nicotinic acetylcholine recepters

21. HISTORY
• In 1978, an actinomycete was isolated at the kitasato
institute from a soil sample collected at kawana, japan.
• The family of compounds were finally characterized by a
team at merck in 1978.
• In 2002, kitasato university and at the kitasato institute,
proposed that streptomyces avermitilis be
renamed streptomyces avermectinius.

22. 1. AVERMECTIN
• From Streptomyces
avermectin
• Major homologues- A1a,
A2a, B1a, B2a
• Minor homologues- A1b,
A2b, B1b, B2b
• B1b and B2b are effective-
abamectin
• GABA agonist
• Vermac –A, albentin,
verbend

23. 2. MILBEMECTIN
• S. hygroscopicum var aureolacromosus
• Have 2 group- A3, A4
• GABA abonists
• milbeknock

24. 3. SPINOSAD
• S. spinosa
• 2 metabolites- spinosin A(C4H65O10),
spinosin D (C4H67O10)
• Against caterpilllars and thrips
• Acts as Ach agonist
• Success 2.5 EC , tracer 45EC

25. VIRAL PESTICIDES

26. GENERAL OVERVIEW
• Insect-specific viruses can be highly
effective natural controls of several
caterpillar pests.
• Stomach poison
• No threat to humans or wildlife is posed by
insect viruses.

27. BACULOVIRUSES
• Rod shaped DNA viruses
• Include NPV and GV
• Pathogenic for lepidoptera(83%),
hymenoptera(10%) and diptera(4%)
• Infection is by ingestion of food

29. • The polyhedrin protein dissolves in the alkaline
environment of the new host's gut and the
occluded virus is released.
• This virus infects the gut epithelial cells and virus
replication takes place.
• Nonoccluded virus is then produced and budded
from the infected gut cells
Mode of action

32. 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
• 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

37. • The recommended dosage is 200 ml of
NPV/acre or 500 ml/ha containing 100 and
250 larval equivalent (LE) of NPV respectively
as active infective material (one LE = 6 x 10^9
pobs).
• Field efficacy 70-80%

38. FUNGAL INSECTICIDES
>750 fungi on insect are reported
• Beauveria
• Metarrhizium
• Paecilomyces lilacinus
• Verticilium lecanii
• Hirsutella thompsoni

39. MODE OF ACTION
• Formation of an infection structure
• Penetration of the cuticle
• Production of toxins
 beauvericin, beauverolides by B.
bassiana
 dextruxines by M. anisopliae

40. LIFE CYCLE

41. B. bassiana
• Infect lepidoptera, coleopteran, hemipteran, and few
diptera and hymenoptera
• Boverin, boverol, boverosil, mycotrop, mycojaal,
metaguard etc
• H. armigera, S. litura, H. consaguinea, coffee berry
borer, rice hispa
M. anisopliae
• Biogreen, metaguino, biopath, bioplast
• Rhinocerous beetle , white grub

42. V. lecani
• Pathogen of homoptera
• Mycolol, vertilec
H. Thompsoni
• Citrus red mite, coconut eriophid mite

43. Entomopathogenic Fungi
1. Metarhizium anisopliae
2. Beauveria bassiana
Green muscardine diseased grub White muscardine diseased grub

45. • Pre-sowing soil application of Beauveria
bassiana and Metarhizium anisopilae @ 10 g/m2
(containing 1012 spores /ha) against white grub
and cut worm larvae, mole crickets, field crickets
and Verticillium lacanii @ 48 X 106/ml is effective
against epilachna beetles
(DUTTA & BHATTACHARYYA,2013)

46. • The entomogenous nematodes Steinernema
feltiae S. Scapteriscae, S. Riobravis, S.
Carpocapsae and Heterorhabditis heliothidis
are the Species most commonly used in
insecticidal Preparations.
• effective against over 400 pest species,
Including numerous beetles, fly larvae, and
Caterpillars.
Entomopathogenic
nematode
G. C. SMART, JR. 1995

50. ADVANTAGES OF EPN
• Biocontrol ability to search ( chemoreceptors ) the
target insect
• broad host range
• easily cultured
• compatibles with many pesticides
• easy delivery system by spraying EPN suspension
or irrigation system
• safe to vertebrates, plants and non-targets and
environmentally safe
• long-term control
•

51. PROTOZOAN INSECTICIDES
• Not suited for short time
• Effective against grasshoppers, mosquitoes, boll
weevils
• They reduce host reproduction or feeding rather
than killing the pest.

52. • Must be eaten to infect an insect, but there many
also be some natural transmission within a pest
population,
• The pathogen enters the insect body via the gut
wall, spreads to various tissues and organs, and
multiplies, sometimes causing tissue breakdown
and septicemia.
• Infected insects may be sluggish and smaller
than normal, sometimes with reduced feeding
and reproduction. Weinzieri, R. and T. Henn. 1989.

53. • Species in the genera Nosema and vairimorpha
Seem to offer the greatest potential for use as
Insecticides.
• Pathogens in these genera attack Lepidopteran
larvae and insects in the order Orthoptera
• Nosema locustae , a pathogen of grasshoppers is
sold as NOLO bait® and grasshopper attack®,
germspore bait®
• Infect atleast 90 sp of grasshopper
• Non toxic to mammals Weinzieri, R. and T. Henn. 1989.

54. Vairimorpha necatrix
• Infect 36 lepidopterans- 20 noctuids
• Mortality due to damage of gut followed by
septicaemia or by microsporidia
• Swelling of fat body is seen

55. Global biopesticide market

56. Biopesticides/Bioagents Quantity/annum (approx)
Bt 50,000 kg
NPV (liquid) 500,000 Le
Beauveria Meager
Annual availability of biopesticides in India
Source: Kalra & Khanuja 2007

57. ADVANTAGES
• Non toxic and nonpathogenic to organisms not
closely related to the target pest.
• often specific to a single group or species of
insects
• Most microbial insecticides can be used in
conjunction with synthetic chemical insecticides
• Residues present no hazards to other animals,
• The pathogenic microorganisms can become
established in a pest population

58. DISADVANTAGES
• Heat, desiccation (drying out), or
exposure to ultraviolet radiation
• pest-specific, the potential market for
these products may be limited

59. REFERENCES
• Integrated pest management- concepts and
approaches by G.S Dhaliwal and Ramesh
arora
• WIKIPEDIA

60. SUPRABHA
PALB4109