Question

Select the correct group of biocontrol agents.
A. Bacillus thuringiensis, Tobacco mosaic virus, Aphids
B. Trichoderma, Baculovirus, Bacillus thuringiensis
C. Oscillatoria, Rhizobium, Trichoderma
D. Nostoc, Azospirillum, Nucleopolyhedrovirus

Answer 1

Crops are eaten up by some insects or worms. They destroy a whole lot of crops thus keeping them away is very important. For this, chemicals like pesticides are used. But at the same time, they are harmful to the plants so the use of microorganisms is preferred.

Complete answer: Biocontrol agents are natural enemies of the pests thus they are used to control the pest damage. For example – parasitic wasps control aphids. Some of the other examples are Trichoderma, Baculovirus, Bacillus thuringiensis. Using microorganisms to control plant diseases and pests are biocontrol. There are various bacterias like Bacillus thuringiensis used for this purpose. Some of the fungal agents are Trichoderma.
TMV – Tobacco mosaic virus is a pathogen which destroys the crop by wilting and yellowing them. Aphids are pests that are harmful to the crops.
Nostoc, Rhizobium, and Oscillatoria are the biofertilizers for the crops. They have the major nutrients needed for the plants to grow.
Option A: Bacillus thuringiensis, Tobacco mosaic virus, Aphids: all belong to different categories – biocontrol agents, pathogen, and pests respectively.
Option B: Trichoderma, Baculovirus, Bacillus thuringiensis : They are all biocontrol agents
Option C: Oscillatoria, Rhizobium, Trichoderma : they are biofertilizers and biocontrol agents respectively.
Option D: Nostoc, Azospirillum, Nucleopolyhedrovirus : they are biofertilizers and pathogens respectively.
So the answer is option B:Trichoderma, Baculovirus, Bacillus thuringiensis

Note: The biological agents work on the mechanism of predation, parasitism, etc. These simple mechanisms are best to use as they are cheaper. They are non-harmful and non-toxic. They will just attack and harm their enemy which ultimately is the enemy of the crop.