What is the main ingredient in most rodenticides?

The main ingredient in most rodenticides is anticoagulants. Anticoagulants function by interfering with the blood's ability to clot, leading to internal bleeding and ultimately causing the death of the rodent over a period of time after consumption. This method allows for a more extended exposure to the bait, increasing the chances of rodents consuming a lethal dose while minimizing the potential of bait shyness or immediate death, which could alert other rodents to the danger.

In contrast, neonicotinoids, pyrethroids, and insect growth regulators are primarily used for insect control rather than rodent control. Neonicotinoids affect the nervous system of insects, pyrethroids act similarly but are synthetic versions of naturally occurring insecticides, and insect growth regulators disrupt the life cycle of insects. None of these are effective mechanisms for targeting rodent populations, highlighting why anticoagulants are specifically chosen and widely used in rodenticide formulations.