Which chemical is an example of an insect growth regulator (IGR) used in mosquito control?

Which chemical is an example of an insect growth regulator (IGR) used in mosquito control?

• A. Methoprene.
• B. Bti.
• C. Bsph.
• D. Pyrethrum.

Answer: (A)

IGRs disrupt development by mimicking juvenile hormones, so mosquitoes don’t reliably molt to the next stage and rarely reach adulthood. Methoprene is a classic juvenile hormone analog used in mosquito control; when added to larval habitats, it prevents proper metamorphosis, leading to fewer adults and a gradual drop in the population. It’s typically applied to standing water where larvae develop and tends to have lower acute toxicity to vertebrates, making it a target-friendly option in integrated mosquito management. In contrast, Bacillus-based products like Bti and Bsph kill larvae through toxins produced by the bacteria, not by interfering with their growth and metamorphosis. Pyrethrum acts more as a fast-acting nerve toxin, causing quick death rather than developmental disruption. So Methoprene best fits the role of an insect growth regulator.

IGRs disrupt development by mimicking juvenile hormones, so mosquitoes don’t reliably molt to the next stage and rarely reach adulthood. Methoprene is a classic juvenile hormone analog used in mosquito control; when added to larval habitats, it prevents proper metamorphosis, leading to fewer adults and a gradual drop in the population. It’s typically applied to standing water where larvae develop and tends to have lower acute toxicity to vertebrates, making it a target-friendly option in integrated mosquito management. In contrast, Bacillus-based products like Bti and Bsph kill larvae through toxins produced by the bacteria, not by interfering with their growth and metamorphosis. Pyrethrum acts more as a fast-acting nerve toxin, causing quick death rather than developmental disruption. So Methoprene best fits the role of an insect growth regulator.