Question

Which of the following is a free-living biocontrol microbial agent for plant pathogen?

• A. $Mucor$
• B. $Trichoderma$
• C. $Rhizobium$
• D. $Glomus$

Answer 1

The correct option is B $Trichoderma$

Definition of biocontrol agents
Biocontrol agents or biopesticides are biological agents like microbes that are used for the control of pests and pathogens.

Significance of $Mucor$
$Mucor$ is a genus of fungi that are usually pathogenic to the plants.

Significance of $Glomus$
Glomus are a genus of fungi that forms a symbiotic association with roots of higher plants. This association is called mycorrhiza and they help in increasing the fertility of the soil. Therefore, they are used as biofertilisers.

Significance of $Trichoderma$
Trichoderma is the genus of free-living filamentous fungi which act against soil-borne pathogens. Certain fungi belonging to this species forms symbiotic association with the plant roots suppressing the growth of other fungus. They act against soil-borne pathogens (for example, pathogenic fungi or nematode eggs) that attack plants, thus conferring disease resistance to the plants.
It can be appropriately considered as a microbe used in biocontrol of pests and pathogens.

Significance of $Rhizobium$
$Rhizobium$ is a symbiotic nitrogen fixing bacteria which can fix atmospheric nitrogen into compounds that can be uptaken and utilised by the plants. Hence, they are frequently used as biofertilisers.
Final answer
(C) Trichoderma