Which one of the following is an example of carrying out blological control of pests/diseases using microbes?

Which one of the following is an example of carrying out blological control of pests/diseases using microbes?
  1. Trichoderma sp. against certain plant pathogens
  2. Nucleopolyhedrovirus against white rust in Brassica
  3. Bt-cotton to increase cotton yield
  4. Lady bird beetle against aphids in mustard

Solution

Bt cotton is Genetically Modified (GM) cotton which has an incorporated gene extracted from the bacterium Bacillus thuringiensis. This gene codes for $B t$ toxin in plant tissues which is harmful only to a small fraction of insects, most notably the larvae of lepidopterans, moths, butterflies, beetles, flies, etc and harmless to other forms of life. So, it is used as biological control of pests/diseases.

Asked in: NEET 2012 (Screening)

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