Statement I: In organic farming, insects that are sometimes called pests are not eradicated but are kept at manageable levels by a system of checks and balances.
Statement II: Trichoderma species are free-living bacteria that are effective biocontrol agents of several plant pathogens.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Only Statement I is correct.
Biocontrol is the use of biological methods to control plant diseases and pests. The organic farmer does not try to wipe out pests but keeps them in check through natural predators and parasites, and uses microbes such as Bacillus thuringiensis and the fungus Trichoderma as control agents.
Statement I: In organic farming, insects that are sometimes called pests are not eradicated but are kept at manageable levels by a system of checks and balances. — True. The organic farmer works to create a system in which such insects are kept at manageable levels by a complex system of checks and balances. Wiping them out would also starve the useful predatory and parasitic insects that feed on them.
Statement II: Trichoderma species are free-living bacteria that are effective biocontrol agents of several plant pathogens. — False. Trichoderma species are free-living fungi, very common in root ecosystems. They do control several plant pathogens, but they are not bacteria.
Only Statement I is correct.
NCERT Extract:
Microbes as Biocontrol Agents – “… The organic farmer, therefore, works to create a system where the insects that are sometimes called pests are not eradicated, but instead are kept at manageable levels by a complex system of checks and balances within a living and vibrant ecosystem.”
Microbes as Biocontrol Agents – “… A biological control being developed for use in the treatment of plant disease is the fungus Trichoderma. Trichoderma species are free-living fungi that are very common in the root ecosystems. They are effective biocontrol agents of several plant pathogens.”