Which statement correctly distinguishes pyrethrins and pyrethroids?

Which statement correctly distinguishes pyrethrins and pyrethroids?

• A. Pyrethrins are natural; pyrethroids are synthetic
• B. Pyrethrins are synthetic; pyrethroids are natural
• C. Both are organophosphates
• D. Both are neonicotinoids

Answer: (A)

Pyrethrins are natural insecticides derived from chrysanthemum flowers, while pyrethroids are synthetic chemicals created to resemble pyrethrins but manufactured in the lab. This natural-versus-synthetic distinction is what sets them apart. Mechanistically, they both act on nerve cells by affecting sodium channels, but their origins differ: one is a botanical compound that breaks down relatively quickly, and the other is a man-made analogue designed for greater stability and longer-lasting effect. The other statements try to group them with entirely different classes—organophosphates or neonicotinoids—whose members have different chemical bases and modes of action, so they don’t apply to pyrethrins and pyrethroids.

Pyrethrins are natural insecticides derived from chrysanthemum flowers, while pyrethroids are synthetic chemicals created to resemble pyrethrins but manufactured in the lab. This natural-versus-synthetic distinction is what sets them apart. Mechanistically, they both act on nerve cells by affecting sodium channels, but their origins differ: one is a botanical compound that breaks down relatively quickly, and the other is a man-made analogue designed for greater stability and longer-lasting effect. The other statements try to group them with entirely different classes—organophosphates or neonicotinoids—whose members have different chemical bases and modes of action, so they don’t apply to pyrethrins and pyrethroids.