Cyclodextrin has detoxification effects on pesticides, for example, the application of herbicides can not only inhibit the killing of weeds, but also have a toxic effect on crops. If cyclodextrin is applied at the same time, it can detoxify. Cyclodextrins also have stable effects on pesticides. Many pesticides are volatile and are not easy to store for long periods. These volatile pesticides are encapsulated by cyclodextrin molecules and can be stored at room temperature for a long time. For example, the powerful insecticide DDVP is a moderately volatile liquid, which can form a stable crystal inclusion complex with betacyclodextrin. When stored at 25 C for 24 hours, the residue of DDVP in the inclusion compound is still 90%. Cyanide trifluoride is a high efficiency and low toxicity pesticide, and it is also one of the pesticides produced and used in China at present. Over a long period of time, uncontrolled large-scale use has resulted in higher resistance to target pests. Three chloro cyanogen has poor chemical stability, easy to oxidize and decompose under light, and short effective period in the field. The inclusion complex of cyanide trifluoride and betacyclodextrin was prepared by saturated solution method. The polarimetry showed that betacyclodextrin and cyanide trifluoride formed 1:1 inclusion complex. The thermal analysis results showed that the thermal stability of three CFCs increased obviously after the inclusion molecules were formed.
Some betacyclodextrin derivatives with higher water solubility, such as methylated-beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin, have very good Solubilization Effects on lipophilic pesticides. For example, the solubility of insecticide deinsecticide urea in water is only 200 mg/kg at 20 C. After embedding with methyl cyclodextrin, the pesticide urea has a good water solubility, which increases the application and effect of deinsecticide.
Cyclodextrin encapsulated pesticides can maintain long-term stability of the active ingredients, only in contact with environmental humidity will be released. The release rate depends on the stability constant of the inclusion compound, which is closely related to the molecular size, structure, polarity and competitive binder of the entrapped component. Therefore, we can select the competitive binders to standardize the package and pesticide to adjust the release mode. Cyclodextrin-encapsulated pesticides can be made into solid powders for standardized application or liquid spraying, and can also be made into various slow-release formulations.