Match List-I with List-II
| List-I | List-II |
|---|---|
| Biocontrol agents | Affected organisms |
| (A) Ladybird | (I) Mosquitoes |
| (B) Bacillus thuringiensis | (II) Aphids |
| (C) Dragonflies | (III) Plant pathogens |
| (D) Trichoderma | (IV) Caterpillars |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A) - (II), (B) - (IV), (C) - (I), (D) - (III)
(A) Ladybird — this matches (II) Aphids. The ladybird is a beetle that feeds on aphids, so it is used to control them.
(B) Bacillus thuringiensis — this matches (IV) Caterpillars. Its spores are sprayed on plants. The caterpillars (larvae of butterflies) eat them, and the Bt toxin kills the caterpillars.
(C) Dragonflies — this matches (I) Mosquitoes. Dragonflies catch and eat mosquitoes, so they help to get rid of them.
(D) Trichoderma — this matches (III) Plant pathogens. It is a fungus that lives in the root region of plants. It is effective against several plant pathogens.
NCERT Extract:
Microbes as Biocontrol Agents – “… The very familiar beetle with red and black markings – the Ladybird, and Dragonflies are useful to get rid of aphids and mosquitoes, respectively. An example of microbial biocontrol agents that can be introduced in order to control butterfly caterpillars is the bacteria Bacillus thuringiensis (often written as Bt). These are available in sachets as dried spores which are mixed with water and sprayed onto vulnerable plants such as brassicas and fruit trees, where these are eaten by the insect larvae. In the gut of the larvae, the toxin is released and the larvae get killed.”