Efficacy of trans-cinnamaldehyde against Psoroptes cuniculi in vitro

The acaricidal activity of trans-cinnamaldehyde was evaluated in vitro on Psoroptes cuniculi. In this study, different concentrations of trans-cinnamaldehyde were tested, and the observed mites mortality was compared with that observed in untreated and treated (Acacerulen R (R)) controls. The morphological changes in P. cuniculi treated with trans-cinnamaldehyde were examined with light microscopy. By the analysis of variance one-way test, up to 8 mu g/ml of trans-cinnamaldehyde gave highly significant (P<0.01) percentages of mite mortality compared with the untreated controls, but only up to 256 mu g/ml, it showed the same efficacy of Acacerulen R (R). At the same time, a bioassay was conducted by exposing mites to varying doses of transcinnamaldehyde in vitro cultures. The resulting data were analyzed by using a time-dose-mortality modeling technique, yielding the parameters for time and dose effects of P. cuniculi. The beta value was 2.01, indicating that transcinnamaldehyde had a good activity to kill P. cuniculi adults. Based on the time-dose-mortality relationships fitted and the virulence indices estimated, trans-cinnamaldehyde is a promising microbial agent for mites control.