There are many records about the insecticidal effect of neem in history. Shennong's herbal classic contains that neem kills three insects. According to the book Gewu Chutan written by Sudongpo, "fleas and lice can be avoided under the mats of Azadirachta azedarach flowers or leaves.". This shows that neem has a long history of avoiding insects. Toosendanin is a kind of tetracyclic triterpenoids extracted from the root bark of Melia azedarach or Melia azedarach, a traditional Chinese medicine to drive Ascaris. Toosendanin has a wide range of pharmacological and insecticidal activities. It has antifeedant, internal drug killing, stomach poisoning and certain growth inhibition effects on insects.

    Toosendanin can significantly inhibit the growth and development of Musca domestica larvae, resulting in delayed development, prolonged development duration, smaller individuals, decreased activity, delayed pupation, and even the formation of permanent larvae that cannot pupate. The 0.5% Azadirachtin insecticidal emulsion prepared with toosendanin as the main raw material is 800-1000 times, and its control effect on cabbage caterpillar is more than 90%, and it has 85% control effect on cabbage armyworm, yellow thorn moth, yellow shougua adult, potato ladybird, tobacco caterpillar and apple leaf curling armyworm. At the same time, it is safe against natural enemies such as ladybird, aphid eating fly and Trichogramma.

        According to the Chinese pesticide toxicity classification standard, toosendanin is a low toxic pesticide. Azadirachtin is a kind of plant insecticide, which has stomach toxicity, contact killing and Antifeedant effects. After feeding and contacting azadirachtin, pests can block the conduction of nerve center, destroy the midgut tissue, various detoxification enzymes and respiratory metabolism, affect digestion and absorption, and lose the function of food taste, so as to resist feeding, resulting in abnormal growth and development of pests and death, or form deformed insects during molting and coma to death. Azadirachtin has high biological activity against a variety of Lepidoptera pests, but has no control effect on stinging and sucking mouthparts pests. It is easy to decompose in the natural environment and is harmless to human and livestock.  

　   BecauseToosendaninAs a natural product, its own characteristics can avoid large-scale chemical synthesis and reduce the degree of environmental pollution to a minimum. The production of toosendanin is only a simple process of extraction and purification. The production process can meet environmental protection requirements and has little environmental pollution. Toosendanin is the only natural product and easy to degrade. Moreover, as an insecticide, it has a special mode of action, and has a slow effect on pests. It has an antifeeding effect or causes pests to dilute, dehydrate, coma and die gradually after feeding. Therefore, it is basically safe for natural enemies of pests and other beneficial insects. Therefore, the possibility of environmental pollution after use is very small, and it will not significantly affect the local ecological balance, so it is more suitable for the requirements of comprehensive prevention and control. It is more in line with the current direction of pesticide development. In terms of action characteristics, it is neither quick acting nor slow-release. It is an intermediate transitional insecticide.

    With the improvement of people's quality of life and the enhancement of environmental protection awareness, the importance of "pollution-free agriculture" and "green food" has become increasingly apparent. Non toxic or low toxic, residue-free and pollution-free drugs have become the inevitable trend of drug development in the future. Toosendanin has no residue and is not easy to produce drug resistance. It can be degraded by itself in the environment. It will not remain in agricultural products and livestock products for a long time or be enriched through the food chain. It will not cause irreversible damage to the environment. It is relatively low toxic to humans and animals. It meets the requirements of green ecological agriculture and animal husbandry for drugs. Toosendanin itself is a plant-based pesticide. Its selective toxicity to mammals meets the safety standard. After use, the disease insects are not easy to develop resistance, and the development and production costs are relatively low. Toosendanin, as a chemical component with clear composition and structure, will be more and more widely used in medicine, agriculture and animal husbandry with the in-depth study of toosendanin.