Course Content
Horticulture
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UPCATET PG / M. Sc. Agriculture

Mechanical Methods

These involve direct physical removal or destruction of insects or prevention of their entry/spread.

Method

Description

Examples / Targets

a. Hand Picking

Manual collection and destruction of large-sized insects.

Caterpillars, bugs, beetles (e.g., Spodoptera, Helicoverpa).

b. Shaking and Beating of Branches

Shaking branches by hand or mechanically to dislodge larvae/adults.

Useful against defoliators and beetles on trees.

c. Banding

Placing sticky bands or barriers around tree trunks to prevent pests from climbing up.

Mango mealy bug, red hairy caterpillar.

d. Wire-Gauge Screens / Fruit Covers

Protect fruits and vegetables from borers and flies.

Fruit fly, fruit borer protection.

e. Trench Digging

Trenches dug around fields to prevent migration of crawling pests.

Locust nymphs, hairy caterpillar larvae.

f. Trapping

Use of various traps to attract and kill pests.

Light trap, pheromone trap, sticky trap, bait trap, sound trap.

g. Flooding & Draining

Flooding or draining fields to kill soil-dwelling insects or larvae.

Rice root weevil, white grubs, termites.

 

Physical Methods

Based on manipulation of temperature, humidity, light, or radiation to control pests.

Method                                     

Description / Mechanism

Examples / Remarks

a. Temperature Control

Heat or cold used to destroy pests.

Flame throwers used against grasshoppers.

b. Grain Drying

Maintain low moisture content to prevent storage pest infestation.

Safe moisture levels:
Cereals: < 12%
Oilseeds: < 8%.

c. Light / Radiation

Light traps attract nocturnal insects; radiation used for sterilization (SIT).

Sterile Insect Technique against fruit fly.

d. Humidity Control

Reducing moisture to discourage fungal and insect growth.

Storage pest control.

 

Legal Control

The government-enforced measures to prevent the introduction and spread of pests from one region to another (nationally or internationally).

Law / Institution

Year / Place

Purpose

DIPA – Destructive Insect Pest Act

1914

First legal act in India to regulate import of plants/seeds and prevent entry of exotic pests.

DPPQS – Directorate of Plant Protection, Quarantine & Storage

1946, Faridabad (Haryana)

Responsible for plant quarantine, pesticide testing, and IPM promotion.

Domestic Quarantine

Implemented for specific pests within India (e.g., banana bunchy top virus, San José scale).

Plant Quarantine (Regulation of Import into India) Order

2003

Latest comprehensive legal framework for plant pest prevention.

 

Biological Control

“The utilization of parasitoids, predators, or pathogens to regulate pest population density.” Term first used by H.S. Smith (1919).

Types of Biological Control Agents

  • Parasitoids

Special type of parasites that kill their host during development; require only one host for completion of life cycle.

Type                             

Example

Target Pest / Crop

Egg Parasitoids

Trichogramma spp.

Eggs of Helicoverpa, Spodoptera, Chilo.

Larval Parasitoids

Cotesia, Bracon hebetor, Campoletis chloridae

Larvae of bollworms and borers.

Pupal Parasitoids

Tetrastichus, Brachymeria spp.

Pupae of cotton bollworm, sugarcane borers.

Main Orders:

  • Hymenoptera: Ichneumonidae, Braconidae, Chalcidoidea, Proctotrupoidea
  • Diptera: Tachinidae (e.g., Tachinid flies)

 

  • Predators

Free-living, larger in size; kill and consume multiple prey during their lifetime.

Predator

Scientific Name

Target Pest

Ladybird beetle

Coccinella septempunctata

Aphids, mealybugs.

Lacewing

Chrysoperla carnea

Aphids, whiteflies, jassids.

Syrphid fly

Syrphus corollae

Aphids.

Dragonfly/Damselfly

Mosquito larvae.

Spiders

Generalist predators in fields.

 

  • Pathogens (Microbial Control Agents)

Diseases caused by microorganisms pathogenic to insects.

Pathogen Type        

Example

Target Pest

Bacteria

Bacillus thuringiensis (Bt)

Caterpillars, bollworms, DBM.

Viruses

NPV (Nuclear Polyhedrosis Virus), GV (Granulosis Virus)

Helicoverpa armigera, Spodoptera litura.

Fungi

Beauveria bassiana, Metarhizium anisopliae, Verticillium lecanii

Whiteflies, aphids, termites.

Protozoa

Nosema locustae

Locusts, grasshoppers.

Nematodes

Steinernema, Heterorhabditis spp.

Soil-dwelling pests.

 

⚙️ Methods of Biological Control

Type

Description

Example

Conservation

Protecting existing natural enemies.

Avoid broad-spectrum pesticides.

Augmentation

Mass release of natural enemies.

Trichogramma chilonis in cotton.

Introduction (Classical)

Import & release of exotic enemies for invasive pests.

Rodolia cardinalis against cottony cushion scale (Icerya purchasi).

 

Important Milestones in Biological Control

Year

Event

1888

Rodolia cardinalis (Vedalia beetle) successfully controlled cottony cushion scale in California – first classical biocontrol success.

1919

Term biological control coined by H.S. Smith.

1964

Book Biological Control of Insect Pests and Weeds by Paul DeBach published – standardized the field.

 

Key Facts for Quick Revision

  • Father of Biological Control: Paul DeBach
  • Father of Applied Entomology: William Kirby
  • Father of Host Plant Resistance: R.H. Painter
  • First Viral Biopesticide Registered (India): Elcar (Helicoverpa NPV), 1975
  • Most used parasitoid in India: Trichogramma chilonis
  • Most used predator: Chrysoperla carnea

 

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