This document discusses a seminar presentation on the role of entomopathogenic microbes in insect management. It provides background on different types of entomopathogenic microbes including bacteria, viruses, fungi, nematodes, and protozoa. It summarizes the history, mode of action, symptoms, and examples of microbial pathogens used against various insect pests in agriculture. Key advantages and disadvantages of using entomopathogenic microbes for insect control are also highlighted.

1. WELCOME

2. Role of Entomopathogenic Microbes
in the Management of Insects
Doctoral Seminar
Speaker
Krishna Gupta
Ph.D. Scholar
on
Seminar In -charge
Dr. S. S. Shaw

3. Introduction:
Entomopathogen

4. Different Types of Entomopathogens
Virus
Bacteria Fungi
Nematodes
Protozoa

6. History of bacteria
• First record on Bacillus thuringiensis in 1901
• Ishiwata discovered a bacterium from diseased silkworm
larvae
• Dr. Berliner received diseased Mediterranean flour moth
larvae from mill in Thüringen (Germany) in 1909
• Bt. was first used as an insecticide against European corn borer
in South East Europe (1930)
• First commercial product, Sporeine was available in France for
control of flour moth (1938)

7. Entomopathogenic bacteria
Spore formers Non-spore formers
E.g. Pseudomonas spp.
Obligate spore formers Facultative spore formers
E.g. Bacillus popillae
Crystelliferous Non-Crystelliferous
E.g. Bacillus thuringiensis E.g. Bacillus cereus
(Dr. D. S. Reddy 2010)

8. Bacillus thuringiensis
• Bt is a Gram-positive, rod-shaped, spore-forming
entomopathogenic bacterium.
• Bt protein toxins are highly selective to their target
insect, are innocuous to humans, vertebrates, plants and
are completely biodegradable.
• Bt is a viable alternative for the control of insect in
agriculture and disease spreading vectors in public
health.
( Ramanujam et. al., 2014)

9. Mode of action

10. Symptoms
• Larvae becomes inactive, stops feeding
• The head capsule becomes large
compared to body size
• The larvae becomes flaccid and dies,
usually within days or a week
• The body contents turn brownish-black
as they decompose.

11. Different Bacillus thuringiensis spp.
used in insect management
• Bacillus thuringiensis var. kurstaki: - Lepidopteran
larvae (butterfly and moth)
• Bt var. israelensis: - Mosquito larvae
• Bt var. sandiego: - Coleopteran larvae (Beetles)
• Bacillus popillae: - Japanese beetle larvae
(Dr. D. S. Reddy 2010)

13. History of virus
• Symptoms of Baculovirus infection in insect were first
recognized in silkworms in 16 century
• Paillot (1926) described the first granulosis disease from
the larvae of Pieris brassicae
• Bergold (1947) provided definitive evidence of the viral
nature of disease
• ELCAR the first commercial viral pesticide produce by
Sandoz Company in 1970

14. Entomopathogenic virus
Baculoviridae
Eubaculovirinae Nudibaculovirinae
(Occluded virus particles) (Non-occluded virus particles)
NPV GV
(Nuclear polyhedrosis viruses) (Granulosis viruses)
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(Dr. D. S. Reddy 2010)

15. Viruses
• Baculoviruses are the most common and most widely
studied group of viruses pathogenic for insects.
• Baculoviruses are rod-shaped particles which contain
circular double stranded DNA genomes.
• Viruses are obligate parasites hence need for
multiplication.

16. • The genus NPV is characterized by the presence of
polyhedral shaped viral occlusions (polyhedra)
containing randomly occluded viral particles.
• The genus granulose virus (GV) has one nucleocapsid
per envelope and has granule shaped viral occlusions
(capsules) containing one or rarely 2 or more virions.
(Dr. T. V. Prasad)
Conti….

17. Mode of action of virus

18. Symptoms
• They have a characteristic shiny-
oily appearance and stop feeding.
• They climb to the top of the crop
canopy, becomes limp, and hang
from the upper leaves or stems,
hence the common name
“caterpillar wilt” or “tree top”
disease.
• NPV – infected larvae may
initially turn white and very dark

19. Different viruses used in insect
management
• NPVs of Amsacta albistriga and A. moorei are used on
groundnut for the control of red hairy caterpillers.
• Ha – NPV is used for the control of Helicoverpa armigera
on chickpea and groundnut.
• Sl – NPV is used for the control Spodoptera litura on
tobacco, groundnut, black gram and cotton.
• GV of Chilo infuscatellus is used for the management of
shoot borer on sugarcane
(Canan usta 2013)

21. • Entomopathogenic fungi reproduce sexually in soils
and asexually in insect hosts.
• In its asexual form it produces spores known as
conidia which are wind dispersed.
• It is usually need moisture to enable infection, and
natural epizootics are most common during wet or
humid conditions.
(Maina, et. al., 2018)
Entomopathogenic Fungi

22. History of fungi
• Louis Pasteur was the first to use fungus on grape vines in the
vine yards to control the tiny inhabiting insect
• Beauveria spp. was discovered in 1835 as cause of the
Muscardine disease of domesticated silkworms
• Verticillium lecanii was first observed in Ceylon (Sri lanka) in
1861 on diseased Lecanium coffeae
• In 1879 and 1888 produced the fungus, Metarhizium
anisopliae to control the wheat cockchafer and sugarbeet
weevil

23. Mode of action of fungus
Mode of action

24. Symptoms
• Infected insects stop feeding and becomes lethargic.
• They may die relatively rapidly, sometimes in an
upright position still attached to a leaf or stem.
• The dead insect’s body may be firm and “cheese
like”.
(Dr. T. V. Prasad)

25. Different fungus used in insect
management
• Beauveria bassiana: -They are used
particularly to control sucking pests and
caterpillars infesting crop plants.
Spodoptera litura

26. Conti….
• Metarrhizium anisopliae – This pathogenic fungus is
used to control mainly coconut rhinoceros beetle,
groundnut cut worm, rice brown plant hopper,
diamond back moth and early shoot borer, top shoot
borer and internode borer of sugarcane etc.
Grass hopper
Rhinoceros
beetle grub
Effected by Metarhizium anisopliae

27. Conti….
• Nomuraea rileyi – It is used to control pod
borers, cut worms, cabbage borers etc.

28. Conti….
• Verticillium lecanii – This beneficial fungus is
mainly used to control whiteflies, aphids,
thrips, brown plant hopper, scale insects,
mealy bugs and other sucking insect pests of
crop plants.
Green scale

29. Hirsutella thompsonii – These fungi are used to control
different hoppers and bug pests, whiteflies, mites etc
Coconut mite
Citrus rust mite
Conti…..

31. • Entomopathogenic nematodes are soil-
inhabiting, lethal insect parasitoids, live inside
the body of their host.
• The most commonly studied genera are those
that are useful in the biological control of
insect pest, the Steinernematidae and
Heterorhabditidae.
Entomopathogenic nematodes (EPN)

32. History of EPN
• The first entomopathogenic nematode was described by Steiner as
Aplectana kraussei (now Steinernema kraussei) in 1923
• The genus Heterorhabditis was described in 1976.
• In 1981, BR company supply S.carpocapsae on crickets and
packaged a product called Neocide for use against the carpenter
worm.
• In 1982, “The California Nematode Laboratories” was to
produced the first commercial products, BioSafe, BioVector, etc
from Steinernema spp.

33. Mode of action

34. Different nematodes used in insect
management
• Steinernema carpocapsea – Against for lepidopterous larvae.
• S. faltiae – It is used for dipterous insects.
• Heterorhabditis bacteriophora – Soil-dwelling insects
Nematodes in beet armyworm pupa (left) and termite worker (right)

35. Entomopathogenic protozoan
• Entomopathogenic protozoans
are extremely diverse group of
organisms comprising around
1000 species.
• They are generally host specific
and slow acting.
• Producing chronic infections
with general debilitation of the
host.
(Ramanujam et al. 2014)

36. • The first protozoa were seen by Antony van
Leeuwenhock in 1674
• Linnaeus included 2 species of free-living Protozoa in
the 1758 edition of his Systema Naturae
History of Protozoa

37. Mode of action
Microsporidia must be eaten to infect an insect
The pathogen enters the insect body via the gut
wall, spreads to various tissues and organs
These are relatively slow acting organisms,
taking days or weeks to debilitate their host

38. Symptoms
• Infected insects may be sluggish and smaller
than normal.
• Reduced feeding and reproduction, and
difficulty in molting.
• Death may fallow if the level of infection is
high.

39. • Nosema locustae is used for the control of
grasshoppers and crickets.
• Vairimorpha necatrix is used for the control of corn
earworm, European corn borer, various armyworms
and cabbage looper.
• Farinocystis triboli is used against red flour beetle.
Different Protozoa used in insect
management
(Dr. T. V. Prasad)

40. Advantages of Entomopathogenic
microbes
• These are species- specific and hence safe to beneficial
insects.
• Environmentally safe and safe to non target organisms.
• Compatible with other chemical insecticides.
• These are easy to apply.
• It is self sustaining and so economical.

41. • Efficacy depend on environment conditions.
• Some pathogen (protozoan) are difficult to mass
produce.
• Necessity of correct timing of application
• Results are not as quick as insecticides.
• Awareness among farmers is needed to adopt.
Disadvantages of Entomopathogenic
microbes

42. Example of entomopathogenic microbes
A. Bacteria Targets insects Crop Product name Doses / ha.
1. Bacillus thuringiensis var.
Kurstaki
Lepidopteran larvae (butterfly and
moth)
Gram, chickpea Novodor, caterpillar killer,
javelin, etc
1.5-3 kg
0.75-1.0 lit.
2. Bt var. Israelensis Mosquito larvae Skeletal, teknar, mosquito attack
3. Bt var. Sandiego Coleopteran larvae (Beetles) Storage crop Novardo, trident.
4. Bacillus popilliae Japanese beetle larvae Roses, grapes Doom, japidemic, grub attack 0.5-1 kg
B. Virus
1. NPV Helicoverpa armigera and
Spodoptera litura
Tobacco, Soybean Gypchek virus 1.5-3.0 x 1012 POB
(250-500 LE)
2. GV Chilo infuscatellus, Achaea janata,
Phthorimaea opercullela
Sugarcane, potato Agrovir, madex 250 LE or 750
virosed larvae
C. Fungi
1. Beauveria bassiana Whiteflies, aphids, thrips Glasshouse tomata/
ornamentals
Mycotrol / botanigard 42.5x1010 spore /
m3 or 2-3 kg dust
2. B. bassiana Sucking insects Cotton Naturalis
3. Verticillium lacanii Whiteflies, Aphids, Scales Glasshouse crop Vertalec 10x106 spores /ml
4. Metarrhizium anisopliae Termites House Bioblast 42.5x1010 spore / m3
5. M. anisopliae BPH, GLH Rice Bio magic
6. Nomouraea rileyi H. armigera. Achaea janata, S. litura Cotton Numoraea 10x1010 spores /ml
7. Hirsutella thompsonii Mites Citrus Mycohit 1-5 g/ l of water
D. Nematodes
1. Steinernema carpocapsea Larvae of soil-dwelling and boring
insects
Biosafe, ecomask, scanmask 1 lit. / 400-500 lit.
water
2. Heterorhabditis heliothidis Soil-dwelling insects
E. Protozoans
1. Farinocystis triboli Red rust flour beetle
2. Nosema locustae Grasshopper, European cornborer Nolo balt, grasshopper attack
3. Vairimorpha necatrix Corn earworm, armyworms, cabbage
looper
Cabbage , sorghum
(Source: Ramanujam et al 2014, Canan Usta 2013, J. Alice et al., 2014, Maina UM, et al 2018 and Dr. T.V. Prasad)

43. Conclusions
The application of entomopathogenic microbes for insect
control is increasing largely because of
• Greater environment awareness.
• Food safety concerns.
• The failure of conventional chemicals due to an
increasing number of insecticide resistant species.
• They provides us significant and selective insect control.