Biological Control agents ,their types, advantages and disadvantages

1. BIOCONTROL AGENTS
Presented By:
RAKSHANDA NATH (BSBN1BT18015)
Tejasv Gupta(BSBN1BT18026)

2. Contents
 Introduction
 History
 Types of Biocontrol
 Strategies of biological pest control
 Types of Biocontrol Agents
 Advantages
 Disadvantages
 Conclusion
 References

3. What is Biocontrol ?
 Biocontrol is the application of one living organism
to control another: also referred to as a biological
pest control.
 The aim of biocontrol is not to eradicate the
invasive species, but control it in a way that it
becomes manageable. In other words, the method
uses nature’s own in-built mechanisms to ensure
equilibrium.
 It is a self-sustaining and long-term treatment
method, for managing invasive plants and pests.
 The living organism applied in this system is used
to suppress a weed infestation. Furthermore to
control pests (including insects, pathogens, and
grazing animals).

4. Biocontrol Agents
 Biological control or biocontrol is a method of
controlling pests such as insects, mites, weeds and plant
diseases using other organisms.
 It relies on predation, parasitism, herbivory, or other natural
mechanisms, but typically also involves an active human
management role.
 They play an important role in controlling the plant
pests like parasitic nematodes, weeds, parasitic
nematodes, and mites.
 The biological control agent helps in maintaining and
balancing the plant species along with their natural
enemies.

5. History
 The term "biological control" was first used by Harry Scott
Smith in 1919 .
 It was brought into more widespread use by the
entomologist Paul H. DeBach who worked on citrus crop
pests.
 Riley in 1873, shipped the predatory mites Tyroglyphus
phylloxera to help fight the grapevine phylloxera
(Daktulosphaira vitifoliae) that was destroying grapevines
in France.

7. Types Of Biocontrol
 Inundative Biocontrol
i. This approach uses pathogens, applied on a target weed at
a very high rate in an aspect that is almost similar to
herbicide application.
ii. The most common pathogens used in inundative bio-
control include parasitic nematodes and nuts.
iii. This approach does not prevent the invasive plant from
increasing at a later date.

8.  Classical Biocontrol
 It uses agent populations that would waver in a natural
prey and predator relationship.
 This method adopts natural predatory insects of the
invasive plant.
 It creates an eternal relationship between a plant and
biological control animals.

9. Strategies of Biological Pest
Control
Classical (importation), where a natural
enemy of a pest is introduced in the hope
of achieving control.
Inductive (augmentation), in which a
large population of natural enemies are
administered for quick pest control.
Inoculative (conservation), in which
measures are taken to maintain natural
enemies through regular reestablishment.

10. Types of Agents
 Parasitoids
 Predators
 Entomopathogens
i. Entomopathogenic Bacteria
ii. Entomopathogenic Baculoviruses
iii. Entomopathogenic Fungi
iv. Protozoans
v. Entomopathogenic Nematodes(EPN)

12. Parasitoides
 An organism that during its
development live in or on
the body of the host,
eventually kills the host in
process of parasitism.
 Types of Parasitoid:
• Egg Parasitoid: eg- small
worm
• Larval Parasitoid: eg-
Apanteles
• Pupal Parasitoid: eg-
Xanthopimpla spp.
• Adult and Nymphal
Parasitoid: eg- Epricania
melenoleuca

13. Predators
 These consume on many prey
over the course of their
development, they are free
living and they are usually are
big as their prey or bigger.
 Some predators are only
predaceous only in their
larval stage like syrphid fly.
 Other predators are found in
field in the different cropping
system are lad beetle, praying
mantis, etc.

14. ENTOMOPATHOGENS
→

15. Entomopathogenic
Bacteria
 Example - Bacillus
thuringiensis (B.T.)
 Larvae consume foliage
treated with Bt.(spores and
crystals).
 BT-endotoxin attack on
mid gut.
 The mid gut wall
breakdown allowing Bt.
into the haemocoel and
killing the larvae into 1-2
days.

16. Entomopathogenic
Virus
 Example - Nuclear
Polyhedrosis Virus (NPV)
Infection of baculovirus
generally occur by ingestion
occulded or free virion.
Ingested virion attack mid gut-
occulded bodies dissolve by
protease enzyme
Free virion reach haemocoel,
circulatory system and
respiratory system and attack
there.

17. Entomopathogenic
Fungi
 Example - Beauveria spp. &
Metarhizium spp.
 Spores (conidia) contact with
integument, germinate and
develop hyphae.
 Hyphae enter in haemocoel
and develop mycelium.
 Produce toxin- insect die.

18. Protozoa
Pathogen
Protozoa kills the insects either directly or
by reducing the fecundity of the adult
and their effect on the host is chronic.
The prolong the larval life in the field,
thus exposing the insect longer to
predators and parasitoids.
Infected insect may be sluggish and
smaller than normal.
eg: Nosema melolonthae against
chaffer beetles
Nosema locustae against grass
hoppers.

19. Entomopathog-
enic Nematodes
 These are soil inhabiting, lethal
insect parasitoids
 These live inside the body of
the host, and so they are
designated endoparasites.
 The most commonly studied
genera are those that are useful
in the biological control of
insect pests the Steinernema
and Heterohabditis.

20. Advantages
 The biological control agents are environmentally
friendly and cause no side effects.
 Decrease disease intensity.
 Safe for the users and the farming community.
 Provide natural long term immunity to crops and soil.
 Play a key role in integrated management of diseases.
 Reduce undesirable effects from chemical pesticide.
 Easily available, easy to use and is effective throughout
the season.

21. Disadvantages
 Deleterious effects on non-target microorganisms.
 Pathogens may develop resistance to the biocontrol
agent.
 Seasonal/weather phenomena can make biocontrol agent
ineffective.
 It affects the product quality.
 Pest is not completely destroyed by these biological
control agents.
 It is effective only for large scale.

22. Conclusion
 "Biological control" or "biocontrol" is a process of
controlling pests such as "mites, insects, weeds and plant
diseases" using some other animals.
 Biological control agents offer an eco-friendly and
economic alternative to use of toxic chemicals for control of
various parasites.
 Biological control can have side-effects
on biodiversity through attacks on non-target species by
any of the same mechanisms, especially when a species is
introduced without thorough understanding of the possible
consequences.

23. References
 https://en.wikipedia.org/wiki/Biological
_pest_control
 https://hicare.in/blog/different-types-
biological-pest-control-agents/
 http://www.biocomes.eu/
 https://www.cabi.org/what-we-
do/invasive-species/biocontrol/
 https://www.slideshare.net/ravindra43/
bio-control-agent

24. THANK YOU