Osthol compound is the first pesticide in China. Although the crude extract of Osthol plant has been reported by researchers in Taiwan, Japan, South Korea, Sweden and other countries that it has antibacterial activity in the laboratory, it has never been developed into a commercial pesticide, nor has the activity of the compound been reported. However, Osthol has been developed as a biological pesticide in China and has been promoted and tried in many provincial demonstration sites. The demonstration effect and prospect are gratifying.

    Osthol is a substance extracted from the fruit of Fructus Cnidii, an annual herb in the Umbelliferae family. Its appearance is yellow green to white crystalline powder. Its trade names are tianhuichongqing and GUAXI. Nowadays, it is generally used as field insecticide and bactericide. It is mainly used for contact killing, supplemented by stomach toxicity. The liquid medicine is absorbed into the insect body through the body surface, acting on the nervous system of the insect, causing the non functional contraction of the insect muscle, and finally dying of exhaustion. It has a good contact killing effect on a variety of pests such as cabbage caterpillar, tea geometrid, cotton bollworm, beet armyworm and various aphids. It has good control effect on many Lepidoptera pests and Homoptera pests; It can control various vegetable diseases such as powdery mildew and downy mildew. The main preparation is 0.4% emulsion and 1% water emulsion (GUAXI). So what are the advantages of Osthol as a new biological pesticide?

    Osthol has three significant advantages as a biological pesticide:

    First, slight toxicity. The acute oral and percutaneous LD50 ♂、♀& gt;5000mg/Kg，  It has no irritation to eyes and skin, and the sensitization rate is 0. It is a weak sensitizer. It is non-toxic to bees and birds in the field.

    Second, efficiency. Osthol inhibits chitin deposition on insect body wall and fungal cell wall, showing insecticidal and antibacterial activity. It can also inhibit spore production, germination, adhesion, invasion, germ tube elongation and the nervous system of pests. Therefore, when only 1g of Osthol is sprayed per 667 square meters, the control effect on pests and diseases can reach 85% ~ 95%, which is equivalent to that of chemical pesticides. Break through the previous biological pesticide environmental protection but not efficient.

    Third, no residue. Osthol content in soil could not be detected by HPLC; The residue in cucumber fruit could not be detected 3 days after treatment, so the residue time in the environment was short and there was no pollution to the environment.

    Due to the high environmental protection characteristics of osthol, such as raw material, processing, no residue and non toxicity, it has met the requirements of "organic agriculture", which is the highest level in agricultural production. It has been approved by ecocert , the most authoritative organic certification body in the EU; After international communication, the agency preliminarily believes that the products meet the requirements of EU organic agriculture and is in the process of final certification.

    But in useOstholThere are also some precautions: when applying the drug, it needs to be applied during the incubation period. The effect was good in sunny evening and cloudy day. It is highly toxic to silkworms and forbidden in mulberry gardens. It is forbidden in seedling and legume crops. It is forbidden to mix with alkaline substances and copper agents.