What is the primary function of botanical and synthetic pyrethroids as insecticides?

The primary function of botanical and synthetic pyrethroids as insecticides is to interfere with the insect's physiology, particularly their nervous system. Pyrethroids act by targeting the voltage-gated sodium channels in the nerve cells of insects. When the pyrethroids bind to these channels, they cause them to remain open longer than normal, which leads to uncontrolled nerve firing. This disruption in nerve function results in paralysis and ultimately death of the insect.

While long-lasting residual effects can be a characteristic of some pyrethroids, their primary mechanism of action is their direct interference with insect physiology, not just their persistence in the environment. Additionally, pyrethroids do not primarily function by inhibiting cholinesterase, which is a mechanism associated more closely with other classes of insecticides like organophosphates. Likewise, the disruption of normal development is not the main action of pyrethroids, as these compounds are more focused on immediate neurological effects rather than developmental impacts.