What stage in a flea's life cycle does Insect Growth Regulator (IGR) primarily affect?

Insect Growth Regulators (IGRs) are specifically designed to disrupt the normal growth and development processes of insects. In the case of fleas, IGRs primarily affect the larvae stage of their life cycle.

During the larvae stage, fleas undergo significant metamorphosis as they develop into adults. IGRs inhibit the ability of the larvae to mature properly, resulting in developmental abnormalities or mortality before they can reach adulthood. By targeting this critical life stage, IGRs help to reduce the overall flea population effectively, as fewer larvae will grow into adults, which are responsible for reproduction and further spreading the infestation.

While eggs, pupae, and adult fleas are also essential stages in the life cycle, IGRs primarily exert their effects on larvae, making this choice the most accurate regarding their primary impact.