The principle of pesticides is mainly to cause the death of pests by interfering with the nervous system or physiological processes of pests. Different types of pesticides act on different targets of pests, including inhibiting key enzyme activities, blocking nerve conduction or disrupting physiological balance. The following is a detailed classification of the main mechanisms of action:
Inhibition of acetylcholinesterase (AChE)
Organophosphorus (such as chlorpyrifos, malathion) and carbamate (such as carbofuran) pesticides inhibit acetylcholinesterase in pests, making it impossible for the neurotransmitter acetylcholine to decompose, resulting in continuous excitement of the nervous system and eventually paralysis and death.
Acting on nerve receptors
Neonicotinoids (such as imidacloprid and thiamethoxam) bind to nicotinic acetylcholine receptors (nAChR), interfere with nerve signal transmission, and cause paralysis after excessive excitement of pests.
Spinosad (such as spinosad) allosterically activate nAChR, and also cause death through abnormal nerve conduction.
Ion channel effects
Pyrethroids (such as cypermethrin) keep sodium channels open, causing abnormal nerve excitement and eventually paralysis in pests.
Avermectins (such as avermectin) activate glutamate-gated chloride channels, causing paralysis in pests.
Other physiological disturbances
Insect growth regulators disrupt the molting or cuticle formation process of pests, hindering their normal development.
Biological insecticides (such as Bacillus thuringiensis) produce toxins that damage the intestines of pests, causing them to stop eating and die.
