Which of the following is an anti-adult mosquito insecticide?
**Core Concept**
The question is testing the student's knowledge of larvicides vs. adulticides in vector control, specifically in the context of mosquito-borne diseases like malaria and dengue fever. Adulticides are substances used to kill adult mosquitoes, which are the primary vectors of these diseases.
**Why the Correct Answer is Right**
The correct answer, **B. Permethrin**, is an adulticide used to control adult mosquitoes. It works by disrupting the insect's nervous system, causing paralysis and death. Permethrin is a pyrethroid insecticide, which acts on the sodium channels in the insect's nerve cells. This leads to an influx of sodium ions, causing hyperexcitability and ultimately, death.
**Why Each Wrong Option is Incorrect**
**Option A:** is incorrect because it is not an adulticide. **Option C:** is incorrect because it is a larvicide, used to control mosquito larvae in standing water. **Option D:** is incorrect because it is a repellent, used to prevent mosquitoes from biting humans.
**Clinical Pearl / High-Yield Fact**
It's essential to note that adulticides are often used in conjunction with larvicides as part of integrated vector management (IVM) strategies to control mosquito populations. IVM involves a combination of methods, including larval control, adult control, and environmental modifications, to reduce the incidence of mosquito-borne diseases.
**Correct Answer:** B. Permethrin