Question

Which one is the most effective and most commonly used repellent to control insect?

• A. Rutegar-622
• B. Deet (Di ethyl meta-toluamide)
• C. Oil of citronella
• D. Indalone

Hint:

DEET is the "Gold Standard."
If you see "Di ethyl meta-toluamide" or "DEET," it is almost always the answer for the most effective repellent.
It makes the human "invisible" to the mosquito's nose.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify the gold standard insect repellent used globally for personal protection against mosquitoes, ticks, and other biting insects.

Step 2: Detailed Explanation:

• What is DEET?
DEET (N,N-Diethyl-meta-toluamide) was developed by the U.S. Army in $1946$ for use by military personnel in insect-infested areas.
It was registered for public use in $1957$ and has since become the most common active ingredient in insect repellents.

• Mechanism of Action:
DEET does not kill insects. Instead, it works by confusing their sensory organs.
It blocks the insect's ability to "smell" the chemicals that humans emit (like lactic acid and carbon dioxide), making it difficult for the insect to locate and bite a person.

• Comparison with Other Options:
Oil of Citronella: A natural plant-based oil. While effective, it is highly volatile and provides protection for a very short duration (often less than an hour).
Indalone: An older synthetic repellent used in the mid-$20$th century but largely replaced by the more effective DEET.
Rutegar-622: A specific repellent formulation, but not as universally recognized or effective as DEET.

• Safety and Efficacy:
DEET is remarkably effective, with protection times ranging from $2$ to $12$ hours depending on the concentration. It is considered safe for humans when used according to label instructions.

Step 3: Final Answer:
DEET (Di ethyl meta-toluamide) is the most effective and commonly used insect repellent.