DDT AND THEIR use ,management and evaluation

COURSE TITLE – TOXICOLOGY OF
NSECTICIDES
SUBMITTED TO –
Dr. MUKESH KUMAR MISHRA
ASSISTANT PROFESSOR
DEPARTMENT OF ENTOMOLOGY
SUBMITTED BY-
SUPRIYA SINGH
ID NO. 3129
DEPARTMENT OF ENTOMOLOGY
College of Agriculture
Banda University of Agriculture and Technology Banda
210001 U.P.
ASSIGNMENT
on
MICROBIAL INSECTICIDES
COURSE CODE – ENT-506

MICROBIAL INSECTICIDE
 Microbial control refers to the exploitation of disease causing organisms
to reduce the population of insect pests below are the damaging levels.
 Microbial insecticides are biological preparations that are often delivered
in ways similar to conventional insecticides.
 Microbes and microbial products used as insecticides Less harmful ,fewer
environmental effects.
INTRODUCTION

Micro-organisms which are used as microbial insecticide:
1. Bacteria
2. Viruses
3. Fungi
4. Nematodes
5. Protozoans
Entomopathogenic Bacteria
Spore formers Non Spore formers
Eg: Pseudomonas spp.
Obligate spore formers
Eg: Bacillus popillae
Facultative spore formers
Crystalliferous
Eg: B. thuringiensis
Non Crystalliferous
Eg: B. cereus

 It is a crystalliferous, spore forming bacterium.
 It was isolated by Berliner in 1915 in Germany from the diseased larvae of
mediterranean flour moth, Ephestia kuhniella.
 It is most effective against insect having alkaline gut contents (pH 9.0- 10.5).
 It is marketed under the trade names Bakthane, Dipel, Biotrol, Agritrol, etc.
 Bt is very pathogenic to many Lepidopterous larvae
 Bt produce alpha – Exotoxin, Beta exotoxin, Gamma exotoxin
Bacillus thuringiensis

Symptoms of Bt.
 Larvae becomes inactive, stop feeding.
 The head capsule becomes large compared to body size.
 The body contents turn brownish black as they decompose.
Uses-
 Bacillus thuringiensis Var. galleraie is used against wax moth.
 Bacillus thuringiensis Var. kurstaki is used against lepidoptera
 Bacillus popillae – An obligate spore forming bacteria widely
employed for the control of Japanese beetle.

Mode of Action of Bacillus thuringiensis

 Nuclear polyhedrosis viruses (NPV)
 Cytoplasmic polyhedrosis viruses(CPV)
 Granulosis viruses(GV)
 Nuclear polyhedrosis viruses (NPV)
 Baculoviruses are the most common.
 2nd
and 3rd
instar larvae are highly susceptible to NPV.
 The NPV has been very effective against lepidoptera.
 The genus NPV is characterized by the presence of polyhedral shaped viral
occlusions(polyhedra) containing randomly occluded viral particles .
 Polyhedrosis are characterized by the formation of polyhedron shaped inclusion
bodies in the infected tissues of the host.
 Polyhedra are crystal like with many faces and are made up of concentric layers .
Entomopathogenic Viruses

Symptoms:-
 The larvae have a shiny oily appearance and stop feeding.
 They climb on the top of the crop canopy, become 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 granular or very
dark .
Uses-
 NPVs of Amsacta albistriga and A. moorei are used on groundnut for the control of red
hairy caterpillars.
 Ha- NPV – Helicoverpa armigera on chickpea and groundnut.
 Sl- NPV – Spodoptera litura on tobacco.
 GV of Chilo infuscatellus – Shoot borer of sugarcane.

 NPV particles are called polyhedral inclusion bodies (PIBs) .
 Eaten by the larvae for infection to occur.
 The NPV which enters the insect gut, lyses in the alkaline environment of the mid
gut, releasing virions.
 Virions invade the columnar cells of midgut epithelium and integrate DNA.
 Viral DNA takes over the control of the cellular machinery to reproduce itself.
 The progenies released into the haemocoel are more infectious then the PIBs.
 A rapid spread of infection in the insect body leads immediately to cessation of
feeding followed by death.
 Death from a virus infection usually occurs within 3-8 days.
Mode of Action

 The first pathogens found to cause diseases in insects were fungi because of
their conspicuous macroscopic growth on the surface of their hosts.
 They reproduce sexually in soil and asexually in insect hosts.
 In asexual form it produces spores known as conidia which are wind dispersed
 Usually need moisture to enable infection and natural epizootics are most
common during wet or humid condition.
 The important genera are Coelomomcyces, Entomophthora, Massospora, etc.
Toxins produced by Entomopathogenic Fungi
Fungus Toxin Produced
Beauveria bassiana Beauvericin
Isaria Isarin
Verticillium Beauverolides
Aspergillus spp. Aflatoxin
Entomopathogenic Fungi

Symptoms
 Infected insects stop feeding and become lethargic.
 Discolored patches on integuments and increased acidity in blood.
 The dead insects body may be firm and cheese like
Uses
 Beauveria bassiana causes a disease known as the white muscardine. It is effective
against European corn borer, codling moth, cabbage caterpillar.
 Metarhizium spp. Causes a disease known as green muscardine. It is effective
against rootworm, white grubs and some root weevils.
 Verticillium lecanii is used against white fly, thrips, aphids, especially in green
house crops.
 Hirsutella thompsonii are used against mites.

Commercially available microbial insecticidal
formulations of Fungi
Microorganisms Trade Name Effective Against
Beauveria bassiana Mycotrol, Conidia Sucking pests, Borers
Beauveria brongniartii Betel Scarab beetle larvae
Metarrhizium anisopliae Bio 1020, Bio blast Black vine weevil,
termites
Verticillium lecanii Mycotal Whiteflies, thrips

Introduction
 The first entomopathogenic Nematodes was described by Steiner in 1928.
 Insecticidal properties of Nematodes was discovered by Dutki and Hough in 1955.
 Entomopathogenic Nematodes are soil inhabiting, lethal insect parasitoids.
 They live inside the body of their host, and so they are designated endoparasitic.
 The most commonly studied genera are those that are useful in the biological
control of insect pests, the Steinernematidae and Heterorhabditidae.
Commercially available microbial insecticides formulation of Nematodes
Nematodes spp. Trade Name Effective against
Steinernema carpocapsae Bio vector Lepidopterous larvae
Steinernema scapterisci Proactant Adult molecrickets
Heterorhabditis
bacteriophora
Grubstake HB Soil- dwelling insects
Entomopathogenic Nematodes

 Entomopathogenic Protozoans are extremely diverse group of organism comprising
around one thousand species.
 They are generally host specific and slow acting.
 Producting chronic infection with general debilitation of the host.
 The insect- pathogenic protozoa are currently recorded from four major groups:
I. Amoebas .
II. Gregarines
III. Flagellates
IV. Ciliates
Entomopathogenic Protozoans

Symptoms
 Infected insects may be sluggish and smaller than normal.
 Reduced feeding and reproduction and difficulty in molting.
 Death may follow if the level of infection is high.
Uses -
 These are used against catterpillars, locusts, grasshoppers.
 Nosema locustae is used for the control of grasshoppers and crickets.
 Nosema melolonthae is used against chaffer beetles.
 Vairimorpha necatrix is used for the control of corn earworm, cabbage
looper, European corn borer.

Mode Of Action
 Most microsporidia must be eaten to infect an insect.
 The pathogens enters the insect body via the gut wall.
 Spreads to various tissues and organs and multiplies.
 Sometimes causing tissue breakdown and septicemia.
 These are relatively slow acting organisms, taking days or
weeks to debilitate their host.

Merits
 These are species specific and safe to beneficial insects.
 Environmentally safe and safe to non target organisms.
 Compatible with other chemical insecticides.
 Less chances of development of resistance .
 It is self sustaining and so economical.
 Cost of development and registration is much less than that of chemical
insecticides.
 Easy to apply.
Demerits
 Narrow spectrum.
 Efficacy depend on environmental conditions.
 Some pathogens are difficult to moss production.
 Results are not as quick as insecticides.
 Necessity of correct timing of application.
Merits and Demerits of Microbial Insecticides

DDT AND THEIR use ,management and evaluation

DDT AND THEIR use ,management and evaluation

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