What Are The Insecticide By Source?
1 Inorganic and mineral insecticides. Such as lead arsenate, calcium arsenate, sodium fluorosilicate and mineral oil emulsion. Such insecticides generally have low efficacy and are susceptible to phytotoxicity to crops, while arsenic agents are highly toxic to humans. Therefore, most of the organic synthetic pesticides have been eliminated since they were used in large quantities.
2 Plant insecticides. More than 1,000 plants worldwide have more or less virulence to insects. Commonly used are pyrethrum, fish vine and tobacco. In addition, some plants also contain juvenile hormones, precocious hormones, and ecdysone active substances. For example, camptothecin isolated from the root bark, bark or fruit of Camptotheca acuminata has a strong infertility effect on Dendrolimus punctatus.
3 Organic synthetic insecticides. Such as organochlorine DDT, hexachlorocyclohexane, endosulfan, toxaphene, etc., DDT, hexachlorocyclohexane has been a large-yield, widely used two pesticide varieties, but because of the accumulation in the organism, from the 20th century It was banned or restricted in many countries at the beginning of the year; about 400 varieties of organophosphorus parathion, trichlorfon, dimethoate, etc., yielded the first place in pesticides; carbamate carbaryl , carbofuran, etc.; pyrethroids, fenvalerate, deltamethrin, etc.; organic nitrogens, insecticides, insecticides, etc.
4 Insect hormone insecticides. Such as a variety of juvenile hormones, sex hormones and other analogs (see insect hormone pesticides).
The mechanism of action of a few traditional pharmaceutical agents, such as mineral oil emulsions, mainly acts as physical insecticides on the body surface, and most organic synthetic insecticides enter the pests and interfere with or destroy normal physiological and biochemical reactions at certain sites. Some ways to enter the pests are through the mouthparts into the digestive tract, into the blood, some through the epidermis, and some through the stomata and trachea, the chemicals entering the body and the various enzymes in the body of the biochemical reaction, some reactions Degradation of the agent loses its virulence, but some agents are activated to enhance the virulence. Agents that are not degraded (or activated compounds) exert a toxic effect on certain sites due to different mechanisms of action, such as acting on the nervous system or In the intracellular respiratory metabolic process.
