Toxicity of Stigmasterol Isolated from Crofton Weed, Eupatorium adenophorum Spreng. Against a Rabbit Ear Mite, Psoroptes cuniculi

In order to develop a new type of insecticide, this study lays foundation for the development of stigmasterol from the Eupatorium adenophorum Sprengas nontoxic and pollution-free pesticides that can be released to the environment. The toxicity test of stigmasterol against Psoroptes cuniculi in vitro showed that stigmasterol was toxic under 0.5% concentration. Treatment under this condition also showed mite mortality of 16.67% within 12 h and 23.33% within 24 h. The insecticidal activity of stigmasterol was weaker than that of ageraphorone compound obtained from E. adenophorum Spreng. Through preliminary separation. However, in the experiments, we found an interesting phenomenon, that is, the dead state of mites treated with stigmasterol was similar to that of mites of the positive control group treated with fenvalerate. Furthermore, the dead state of mites treated with stigmasterol was different from that of mites of the negative control group. This result confirmed the insecticidal activity of stigmasterol. We conducted a thorough research on the insecticidal molecular mechanism of stigmasterol to lay the foundation for the development of stigmasterol as nontoxic and pollution-free pesticides that can be introduced into the environment.