Consider the following kinds of organisms: 1. Bacteria 2. Fungi 3. Flowering plants Some species of which of the above kinds of organisms are employed biopesticides?
Contents17
- A1 only
- B2 and 3 only
- C1 and 3 only
- D1, 2 and 3
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Answer: (D) 1, 2 and 3
All three types of organisms are used as biopesticides.
Bacteria:
Bacillus thuringiensis (Bt) is the most widely used biopesticide globally.
Fungi:
Trichoderma and Beauveria bassiana are fungal biopesticides used against crop pests.
Flowering plants:
Neem (Azadirachtin), pyrethrum from chrysanthemum, and rotenone from leguminous plants are plant-derived biopesticides.
So all three — bacteria, fungi, and flowering plants — are used.
Answer: 1, 2 and 3.
Biopesticides from bacteria (Bt), fungi (Trichoderma), and plants (neem) offer alternatives to chemical pesticides and are widely used in integrated pest management.
The question tests whether students know that biopesticides come from all major organism groups, not just plants as commonly assumed.
Biopesticides: Definition & Types
Science And Technology biopesticides
Biopesticides: Natural Pest Control Agents
Biopesticides are naturally occurring substances that control pests using biological mechanisms
Derived from bacteria, fungi, and flowering plants — all three types are commercially used
Bt (Bacillus thuringiensis) is the most widely used bacterial biopesticide globally
Neem and pyrethrum are major plant-derived biopesticides in India
What Are Biopesticides
Biopesticides are pest control agents derived from natural materials like animals, plants, bacteria, and certain minerals. Unlike synthetic chemical pesticides, they use biological mechanisms to kill or repel pests, making them safer for humans and the environment.
Three Main Sources
Source Type | Mechanism | Key Examples | Target Pests |
|---|---|---|---|
Bacteria | Produce toxic proteins | Bacillus thuringiensis (Bt) | Caterpillars, beetle larvae |
Fungi | Infect and kill insects | Trichoderma, Beauveria bassiana | Soil pests, aphids, thrips |
Flowering Plants | Natural toxic compounds | Neem, pyrethrum, rotenone | Wide spectrum of insects |
Why UPSC Tests This
Agriculture policy: Biopesticides are part of India's sustainable farming initiatives
Environmental benefits: Lower toxicity compared to chemical pesticides reduces soil and water contamination
Economic impact: Growing biopesticide market supports rural livelihoods and export potential
Trap: Students often think only bacteria (Bt) are biopesticides, forgetting fungi and plants
Trap: Confusing biopesticides with bioinsecticides — biopesticides include fungicides and herbicides too
Trap: Assuming synthetic biology products are biopesticides — they must be naturally occurring
Bacterial Biopesticides
Science And Technology Bacteria
Bacterial Biopesticides: Bt & Beyond
Bacillus thuringiensis (Bt) produces cry proteins that kill insect larvae
Bt cotton in India uses genetically inserted Bt genes for bollworm resistance
Bacteria work by producing toxic proteins that target specific insect gut receptors
How Bt Works
Bacillus thuringiensis is a soil bacterium that produces crystal proteins (cry proteins) toxic to insect larvae. When insects eat Bt-treated crops, these proteins bind to gut receptors, creating pores that kill the pest.
Major Bacterial Biopesticides
Bacteria | Active Compound | Target Pests | Application |
|---|---|---|---|
Bacillus thuringiensis | Cry proteins | Caterpillars, bollworm | Foliar spray, GM crops |
Bacillus sphaericus | Binary toxin | Mosquito larvae | Water bodies |
Pseudomonas fluorescens | Antibiotics | Fungal pathogens | Seed treatment, soil |
India Context
Bt cotton: Covers over 90% of India's cotton area, reducing bollworm damage significantly
BICP approval: Central Insecticides Board regulates bacterial biopesticide registration
Indigenous strains: Indian Bt strains are being developed for local pest problems
Trap: Bt is often called a 'virus' — it's a bacterium
Trap: Bt kills adult insects — it primarily targets larvae and caterpillars
Trap: All Bt strains work on all pests — different strains target different insect families
Fungal Biopesticides
Science And Technology Fungi
Fungal Biopesticides: Living Pest Killers
Trichoderma species control soil-borne fungal diseases in crops
Beauveria bassiana infects and kills insects through direct contact
Fungal biopesticides work as living organisms that actively seek and destroy pests
Mechanism
Fungal biopesticides are living microorganisms that either compete with harmful fungi for space and nutrients, or directly infect and kill target pests through specialized enzymes and toxins.
Key Fungal Biopesticides
Fungus | Type | Target | Mode of Action |
|---|---|---|---|
Trichoderma harzianum | Biocontrol | Fungal diseases | Competes for nutrients, produces antibiotics |
Beauveria bassiana | Entomopathogenic | Insects | Spores penetrate insect cuticle, kill from inside |
Metarhizium anisopliae | Entomopathogenic | Termites, locusts | Fungal infection through contact |
Paecilomyces lilacinus | Nematophagous | Nematodes | Attacks nematode eggs and juveniles |
Commercial Applications
Trichoderma: Widely used in Indian organic farming for root rot and wilt diseases
Beauveria bassiana: Effective against aphids, thrips, and whiteflies in greenhouse crops
Environmental persistence: Fungal biopesticides can establish in soil and provide long-term protection
Trap: All fungi are plant pathogens — many fungi like Trichoderma protect plants
Trap: Fungal biopesticides only work on fungi — some target insects and nematodes
Trap: Beauveria is a bacterial name — it's an entomopathogenic fungus
Plant-Derived Biopesticides
Science And Technology Flowering plants
Plant-Derived Biopesticides: Nature's Chemistry
Neem (Azadirachtin) disrupts insect hormone systems and feeding behavior
Pyrethrum from chrysanthemum flowers causes insect paralysis and death
Plant biopesticides use secondary metabolites that evolved as natural defense compounds
Rotenone from legume roots is highly toxic to fish but biodegradable
Plant Defense Chemistry
Flowering plants produce secondary metabolites — complex chemicals that defend against herbivores. These natural compounds can be extracted and used as biopesticides, offering pest control with lower environmental persistence than synthetic chemicals.
Major Plant Biopesticides
Source Plant | Active Compound | Mechanism | Target Pests | Extraction Part |
|---|---|---|---|---|
Neem (Azadirachta indica) | Azadirachtin | Hormone disruption, feeding deterrent | 200+ insect species | Seeds, leaves |
Pyrethrum (Chrysanthemum) | Pyrethrins | Nerve paralysis | Flying insects, mosquitoes | Flower heads |
Derris/Lonchocarpus | Rotenone | Blocks cellular respiration | Aphids, thrips, beetles | Roots |
Tobacco (Nicotiana) | Nicotine | Nerve overstimulation | Soft-bodied insects | Leaves |
Karanj (Pongamia) | Karanjin | Growth inhibition | Stored grain pests | Seeds |
Neem Tree Distribution
Source: SNHC Journal — Azadirachta Indica (Neem): A Potential Tree Species for Dry ... · snhcjournal.com
India's Plant Biopesticide Advantage
Neem hub: India produces 60% of global neem-based biopesticides
Traditional knowledge: Farmers have used neem, tobacco, and other plant extracts for centuries
Export potential: Indian botanical pesticides are exported to organic farming markets in Europe and USA
Trap: Only neem is plant-derived — pyrethrum, rotenone, nicotine are also plant biopesticides
Trap: Plant biopesticides are always safe — rotenone is highly toxic to fish
Trap: Synthetic pyrethroids are natural — they're synthetic versions of natural pyrethrins