Question:medium
Which insect among the following is NOT resistant to DDT?
Which insect among the following is NOT resistant to DDT?
Show Hint
The kala-azar vector controlled by DDT indoor spraying is still susceptible to it.
Updated On: Jun 24, 2026
- Musca domestica (housefly)
- Phlebotomus (sandfly)
- Culex fatigans (mosquito)
- Anopheles stephensi (mosquito)
Show Solution
The Correct Option is B
Solution and Explanation
Here we must spot the one vector that has stayed sensitive to DDT while the others have become resistant. Decades of heavy DDT spraying produced selection pressure that bred resistance in many insect populations. Houseflies were among the first to lose susceptibility, and the mosquitoes Culex fatigans and Anopheles stephensi followed, with resistance now common across endemic areas. The sandfly, Phlebotomus, is the exception. Because this vector of visceral leishmaniasis remained susceptible, DDT indoor residual spraying stayed effective and formed the backbone of the kala-azar control and elimination strategy in the Indian subcontinent. Reasoning by elimination, the only insect still vulnerable to DDT among the four is the sandfly. \[\boxed{\text{Phlebotomus}}\]
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