Biology · Microbes in Human Welfare · NEET
The Ladybird is a beetle with red and black markings. It feeds on aphids. Aphids are small insects that damage crops by sucking plant sap. Because the Ladybird kills a pest naturally without any chemical spray, it is called a biocontrol agent. NCERT lists it as a classic example of biological pest control.
The Dragonfly is useful to get rid of mosquitoes. Dragonflies feed on mosquitoes (and their larvae in water). So they help control the mosquito population naturally. This is why NCERT names the Dragonfly right next to the Ladybird as a biocontrol agent.
No. This is a common mistake. Ladybird and Dragonfly are insects (animals), not microbes. NCERT includes them in the biocontrol section because biocontrol uses any living organism — insects, bacteria, fungi, or viruses. So the biocontrol chapter mixes insect predators (Ladybird, Dragonfly) with microbial agents (Bacillus thuringiensis, Trichoderma, Baculovirus).
Ladybird eats aphids. Dragonfly eats mosquitoes. Do not swap them in the exam. NCERT phrasing: 'the Ladybird, and Dragonflies are useful to get rid of aphids and mosquitoes, respectively.' The word 'respectively' means Ladybird goes with aphids and Dragonfly goes with mosquitoes, in that order.
Aphids are pests that feed on plant sap and harm crops. If aphids grow in large numbers, they reduce crop yield. Using the Ladybird to eat them is safer than chemical pesticides, which can pollute soil and water and kill useful insects too.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
It is an insect (a beetle), not a microbe. It is used as a biocontrol agent against aphids.
The Dragonfly gets rid of mosquitoes, so it helps control the mosquito population naturally.
A living organism used to control a pest or disease instead of using chemical pesticides.
NEET often asks matching questions pairing organisms with the pest they control. Knowing Ladybird→aphid and Dragonfly→mosquito helps you avoid the swap trap.
No. They are insect (predator) biocontrol agents. Microbial biocontrol examples are Bacillus thuringiensis, Trichoderma, and Baculovirus.
