This document discusses recent advances in using fungal pathogens as biopesticides. It describes over 750 entomopathogenic fungal species from various phyla that can infect insect populations. Important fungal genera discussed are Beauveria, Metarhizium, and Lecanicillium. The document outlines the mode of action of these fungi, including their ability to produce toxins. It also discusses genetic engineering efforts to improve fungal virulence and stress tolerance. While entomopathogenic fungi offer environmental benefits over chemical pesticides, their use is limited by requirements for specific environmental conditions and lack of persistence under field conditions.

1. Recent Advances in Fungal Pathogens as
Biopesticides
M. M. Mawtham
Ph.D. Scholar
Tamil Nadu Agricultural University

2. Entomopathogenic Fungi
 EPF - over 750 species cause fungal infection in insect
populations
 About 90 genera have been documented to be pathogenic
 EPF requires high humidity
 Optimum temperature for hyphomycetes - 20–30°C
 Wind & sunlight also influence infection process
 Spore dispersal - assisted by wind
 Sunlight & UV - reduce the infection process

3. EPF & its Phylum
 Oomycota - Laginidium giganteum
 Chytridiomycota – Blastocladiales
 Zygomycota – Zoophthora radicans
 Dueteromycota – Beauveria, Metarhizium, Verticillium
 Basidiomycota- Septobasidium

4. Beauveria
 Important species (white muscardine disease)
Beauveria bassiana, B. Brongniartii , B. amorpha & B.
Caledonica.
 The genus Beauveria - 49 species - approximately 22
effective pathogen.
 Originally known as Tritirachium shiotae
 Renamed - Agostino Bassi - muscardine disease in
domestic silkworms (Zimmermann, 2007)

5.  Causes epizootic - used worldwide as a biopesticide to
control a number of pests (termites, whitefly, and malaria-
transmitting mosquitoes).
 Non-selective pesticide
Synnemata

6. Metarhizium
 Metarhizium anisopliae, M. album, & M. flavoviride
 M. anisopliae by Sorokin in 1883.
 Conidiophores aggregated with less verticillate branching
with Phialides in dense, parallel arrangement.
The phialide is a flask-shaped
projection from the vesicle

7. Lecanicillium
 Lecanicillium lecanii and L. Chlamydosporium
 L. lecanii - widely distributed - cause large epizootic in
tropical, subtropical, warm and humid environments.
 Control whitefly & several aphid species

8. New species
 Ophiocordyceps globiceps
 Ophiocordyceps sporangifera
Dipteran and parasitoid wasp
(Xiao et al., 2019)

9. Mode of action

10. Mode of action

11. Toxin Production
 Deuteromycetes - produce different fungal toxins
 Cytotoxins – responsible for cellular disruption prior to
hyphae penetration
 B. bassiana
Beauvericin, beauverolides, bassianolide, and isarolides
 Metarhizium anisopliae
Destruxins (DTXs) & cytochalasins
Paecilomyces – Leucinostatins

13. Insect defense against fungi

14. Mycoinsecticides
 No. of biopesticides Registered in India – 970
 No. of B. bessiana product – 103
 No. of M. anisopliae Product– 30
 No. of L. lecanii Product– 82
(CIB & RC)

15. Mycoinsecticides use for the control of arthropod pests of agricultural crops
(Ramanujam et al., 2014)

16. Commercially available mycoinsectides with their target pest, producer and
country of production
(Mishra et al., 2015)

17. Susceptible hosts of B. bassiana from various insect orders
(Keswani et al., 2013)

18. Formulations
 Wettable powder (WP)
 Granule (GR)
 Bait (Ready to use RB)
 Water dispersible granule (WG)
 Contact Powder (CP)
 Suspension Concentrate or Flowable Concentrate (SC)
 Oil misible Flowable Concentrate (= Oil miscible
suspension (OF)
 Ultra- low volume (ULV) suspension (SU)
 Oil Dispersion (OD)

19. Schematic representation of formulations
development

20. GENETICALLY MODIFIED
ENTOMOPATHOGENIC FUNGI
 Mycoinsecticides currently have a small market share
due to low virulence and inconsistencies in their
performance.
 Genetic engineering has made it possible to
significantly improve the virulence of fungi and their
tolerance to adverse conditions.
Genetic
improvement
Artificial
selection Hybridization Genetic
transformation Mutagenesis

22. Genes and metabolic pathways that have been used to improve
fungal virulence and tolerance to abiotic stresses

23. Contd.,
(Zhao et al., 2014)

24.  Genetic engineering to improve virulence has focused on
reducing both the time to kill and the required lethal
conidial dosage.
 Reducing the amount of fungus required for a fatal
infection allows cost-effective control with increased
effective persistence in the field.
Virulence
(Lovett and Loger, 2015)

25. Identification of novel genes associated
with conidiation in Beauveria bassiana
(Wu et al., 2008)

26. Thermotolerant isolates of Beauveria bassiana
as potential control agent of insect pest
(Alaii et al., 2019)

30. Nano-Entomopathogenic fungi
Schematic representation of synthesis of nanoparticles through biological/green
method (Singh et al., 2015)

34. Benefits of using entomopathogenic fungi
 Their residues have no known adverse effects on the
environment.
 Entomopathogenic fungi are little or non-toxic to non-
target organisms.
 They have narrow area of toxic action, mostly specific to a
single group or few species.
 They can be used in combination with synthetic chemical
insecticides.

35.  They are self-perpetuating under ideal environmental
conditions.
 Reduce chemical insecticide use.
 Protects biodiversity in managed ecosystem.
 Potential development of pest resistance to mycoinsecticde
is less common or may develop more slowly due to unique
mode of action.

36. Limitations of entomopathogenic fungi
 They need specific environmental conditions to germinate
and cause infection.
 Can be very costly to produce for commercial use.
 They have short shelf life
 The pest must be present before the pathogen can be
usefully applied thus making preventive treatment
difficult.

37.  Lack of persistence and low rate of infection under
challenging environmental conditions.
 Often slow acting and require high application rate and
thorough spray coverage.