Dragonflies are biocontrol agents useful for getting rid of:

[Microbes-in-Human-Welfare] [class-xii ]

• Caterpillars
• Aphids
• Mosquitoes
• Weeds
Correct Option: C  [ Mosquitoes ]

Remark: Dragonflies are useful to get rid of mosquitoes.

The bacteria *Bacillus thuringiensis* (Bt) is introduced to control which specific pest?

[Microbes-in-Human-Welfare] [class-xii ]

• Adult mosquitoes
• Aphids
• Butterfly caterpillars
• Root-borne pathogens
Correct Option: C  [ Butterfly caterpillars ]

Remark: Bacillus thuringiensis (Bt) is a microbial biocontrol agent used to control butterfly caterpillars.

When insect larvae eat the spores of *Bacillus thuringiensis*, the toxin is released and kills the larvae in their:

[Microbes-in-Human-Welfare] [class-xii ]

• Lungs
• Gut
• Bloodstream
• Nervous system
Correct Option: B  [ Gut ]

Remark: In the gut of the larvae, the toxin is released and the larvae get killed.

Which fungus is being developed as a biological control agent for the treatment of various plant diseases, common in root ecosystems?

[Microbes-in-Human-Welfare] [class-xii ]

• Penicillium notatum
• Saccharomyces cerevisiae
• Trichoderma
• Aspergillus niger
Correct Option: C  [ Trichoderma ]

Remark: A biological control being developed for use in the treatment of plant disease is the fungus Trichoderma.

Which group of pathogens primarily attack insects and other arthropods, and are often used as biological control agents?

[Microbes-in-Human-Welfare] [class-xii ]

• Protozoa
• Baculoviruses
• Viroids
• Methanogens
Correct Option: B  [ Baculoviruses ]

Remark: Baculoviruses are pathogens that attack insects and other arthropods.

The majority of baculoviruses used as biological control agents belong to which genus?

[Microbes-in-Human-Welfare] [class-xii ]

• Monascus
• Nucleopolyhedrovirus
• Lactobacillus
• Azotobacter
Correct Option: B  [ Nucleopolyhedrovirus ]

Remark: The majority of baculoviruses used as biological control agents are in the genus Nucleopolyhedrovirus.

Baculoviruses are desirable for Integrated Pest Management (IPM) because they have no negative impacts on:

[Microbes-in-Human-Welfare] [class-xii ]

• Beneficial insects
• Plants
• Mammals
• All of the above
Correct Option: D  [ All of the above ]

Remark: They have been shown to have no negative impacts on plants, mammals, birds, fish or even on non-target insects.

Biofertilisers are defined as organisms that:

[Microbes-in-Human-Welfare] [class-xii ]

• Reduce soil pH
• Harm pathogenic microbes
• Enrich the nutrient quality of the soil
• Increase soil water retention
Correct Option: C  [ Enrich the nutrient quality of the soil ]

Remark: Biofertilisers are organisms that enrich the nutrient quality of the soil.

The main sources of biofertilisers listed in the text are:

[Microbes-in-Human-Welfare] [class-xii ]

• Viruses, Viroids, and Prions
• Algae, Lichens, and Mosses
• Bacteria, Fungi, and Cyanobacteria
• Insects, Worms, and Mites
Correct Option: C  [ Bacteria, Fungi, and Cyanobacteria ]

Remark: The main sources of biofertilisers are bacteria, fungi and cyanobacteria.

*Rhizobium* forms symbiotic associations on the roots of leguminous plants primarily to fix:

[Microbes-in-Human-Welfare] [class-xii ]

• Atmospheric carbon
• Atmospheric nitrogen
• Soil phosphorus
• Soil water content
Correct Option: B  [ Atmospheric nitrogen ]

Remark: These bacteria fix atmospheric nitrogen into organic forms, which is used by the plant as nutrient.