UPSC Prelims 2012 Q11: Environment & Ecology – Sustainable Agriculture & Forestry
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 as biopesticides?
- (a) 1 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Answer: (d) 1, 2 and 3
Explanation
Organisms used as biopesticides
A biopesticide is a pest-control agent made from a living organism or a natural product.
| Kind of organism | Used as biopesticide? | Example |
|---|---|---|
| 1. Bacteria | Yes | Bacillus thuringiensis (Bt), which kills caterpillars |
| 2. Fungi | Yes | Trichoderma against plant diseases; Beauveria against insects |
| 3. Flowering plants | Yes | Neem (azadirachtin); pyrethrum from chrysanthemum |
Other biocontrol agents:
| Agent | Use |
|---|---|
| Viruses | Baculovirus (NPV) against insect larvae |
| Insects | Ladybird against aphids; dragonflies against mosquitoes |
Why they matter: they are specific to the pest, leave no toxic residue and are central to Integrated Pest Management.
Answer: (d) 1, 2 and 3.
Why each option is right or wrong
- (a) Incorrect. Fungi and flowering plants also give biopesticides.
- (b) Incorrect. Bacteria such as Bt are the best-known biopesticides.
- (c) Incorrect. Fungi such as Trichoderma are also used.
- (d) CORRECT. Species of bacteria, fungi and flowering plants are all used as biopesticides.
Key point
Biopesticides: Bt (bacterium), Trichoderma and Beauveria (fungi), neem and pyrethrum (plants), baculovirus; used in Integrated Pest Management.
Remember
Biopesticides: Bt, Trichoderma, neem.
Common mistakes
- Thinking biopesticides come only from bacteria.
- Forgetting plant products such as neem.
- Confusing biopesticides with biofertilizers.
Exam tip
Bt, Trichoderma, neem: one each from bacteria, fungi and plants.
Sources
- NCERT Class XII — Biology (Microbes in Human Welfare: microbes as biocontrol agents)
- Central Insecticides Board and Registration Committee — Registered biopesticides