‘Wolbachia method’ is sometimes talked about with reference to which one of the following?

(a) Controlling the viral diseases spread by mosquitoes ✓ UPSC's answer
(b) Converting crop residues into packing material
(c) Producing biodegradable plastics
(d) Producing biochar from thermo-chemical conversion of biomass

Why the answer is (a)

• Wolbachia is a bacterium that lives naturally in many insects; when introduced into Aedes aegypti mosquitoes it blocks the replication of dengue, Zika, chikungunya and yellow-fever viruses inside them.

• The 'Wolbachia method' releases Wolbachia-carrying mosquitoes that breed with wild ones, spreading the bacterium through the population and cutting disease transmission — option (a).

• Trials by the World Mosquito Program in Indonesia cut dengue by about 77%; India's ICMR-Vector Control Research Centre in Puducherry has developed Wolbachia-infected Aedes strains.

• The method has nothing to do with crop residues, bioplastics or biochar.

• Hence option (a).

Why the other options are wrong

(b) Converting crop residues into packing material: Wolbachia is unrelated to crop-residue packaging.
(c) Producing biodegradable plastics: Bioplastics are made from other microbes and plants, not Wolbachia.
(d) Producing biochar from thermo-chemical conversion of biomass: Biochar is produced by pyrolysis, not by Wolbachia.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2023, held on 28 May 2023. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.