Which of the following biocontrol agents is used in the treatment of plant diseases?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Trichoderma
Biocontrol means using living organisms, instead of chemicals, to control pests and diseases. For plant diseases, the book names the fungus Trichoderma. Its species are free-living fungi, very common in the root ecosystem, and they act as biocontrol agents of several plant pathogens.
Option (1) Lactobacillus — Incorrect. Lactobacillus is a lactic acid bacterium that converts milk into curd. It is not used to control plant diseases.
Option (2) Methanobacterium — Incorrect. Methanobacterium is a methanogen that grows anaerobically on cellulose and produces methane in biogas plants. It has no role in plant disease control.
Option (3) Trichoderma — Correct. Trichoderma is the fungus being developed for treating plant diseases. It acts on several plant pathogens in the root zone.
Option (4) Saccharomyces cerevisiae — Incorrect. Saccharomyces cerevisiae is baker’s yeast, used to ferment bread dough and to produce ethanol. It is not a biocontrol agent.
NCERT Extract:
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.”