Evaluation on Acaricidal Activities of Five Plants Extracts against Tetranychus cinnabarinus Boisduval

To screen the efficient bioactive compounds of botanical acaricidal, the acaricidal activities of five plants ethanol extracts against Tetranychus cinnabarinus Boisduval were evaluated using slide-dip method. The results showed that Acalypha australis L. ethanol extracts were virulent against T. cinnabarinus 24 h and 48 h after the treatment than the others at the concentration at 2 mg/mL. The corrected mortality was 33.63% and 85.21% at 24 h and 48 h, respectively. According to the primary test results, A. australis of different polar solvent were used to biological activity tracking. The chloroform extracts of A. australis showed higher acaricidal activity than those of others, with the corrected mortality of 90.28%. Further, A. australis of chloroform extracts was measured using toxicity testing by spraying method. LC50 decreased with contacting time increasing and the lowest value was 2.81 mg/mL after 48 h treatment. Therefore, A. australis of chloroform extracts showed higher acaricidal activity. So this study can provide scientific basis for the development of botanical acaricide.