Gastric poisoning: Insecticides are sprayed on crops or mixed in seeds, and the pests will be poisoned and die after feeding.

Tacticidal effect: Insecticides are sprayed on insects or plant surfaces, and the pests are poisoned and die after contact.

Endosorption: the insecticide is absorbed by plant roots and kills the pests that feed on the sap.

Fumigation: the agent volatilizes to form a gas, which enters the body through the insect's valve and leads to death by poisoning.