Toxicity and Residual Efficacy Ofchlorfenapyr and Emamectin Benzoate Nano-Formulations Compared with Their Conventional Formulations Against Tetranychus Urticae on Cucumber, Cucumis Sativusl

The nanopesticides technology is still in the early stages of development. This technology aims to reduce the use of conventional pesticides and ensure their safe application. However, there are few data about the environmental fate of these new products. This study aimed to evaluate the efficacy of two nano-pesticides chlorfenapyr and emamectin benzoate compared with their conventional formulations against the two-spotted spider mite, Tetranychus urticae on cucumber under green-house conditions. The obtained results showed that the efficacy of nano-formulations was significantly higher than the conventional ones. The LC 50 values were 0.6 and 5.7 ppm in nano-chlorfenapyr and nano-emamectin benzoate, respectively, compared with 3.8 and 10.9 ppm in their conventional formulations, respectively. At the recommended application rate, there is no significant difference in the percentage of red spider ( T. urticae ) reduction between the nano and conventional formulations. Kinetics of the pesticide residues have been determined, the initial deposits after one hour of application were (0.95 and 0.083 ppm) for chlorfenapyr and (0.12 and 0.052 ppm) for emamectin benzoate conventional and nano-formulations, respectively. The pre-harvest interval (PHI) was 7, 5, 3 and 1 day for chlorfenapyr, nano-chlorfenapyr, emamectin benzoate and nano-emamectin benzoate, respectively. This study concluded that the nano-formulation of both chlorfenapyr and emamectin benzoate was more effective than the conventional formulation.