Graphene oxide as a pesticide delivery vector for enhancing acaricidal activity against spider mites.

Synergistic combination of pesticides and nanomaterials has been rarely reported in pest management science at present. In this work, graphene oxide (GO) was synergistically used with three types of pesticides (pyridaben (Pyr), chlorpyrifos (Chl) and beta-cyfluthrin (Cyf) respectively as acaricide against two economically important spider mites Tetranychus truncatus and T. urticae Koch. The results demonstrated that GO can enhance the activity of three types of pesticides. Compared with pesticides, the GO-Cyf, GO-Pyr and GO-Chl mixtures exhibited 1.77-, 1.56- and 1.55-fold higher contact toxicity against T. truncatus, and 1.50-, 1.75-, and 1.78-fold higher contact toxicity against T. urticae. SEM results showed that pesticide can adsorbed on the surface of GO. The synergistic mechanism may be that GO can serve as a carrier of pesticides, which can be adsorbed on the surface of mites and thus improve efficacy and utilization efficiency of pesticides. This kind of GO-based nanoscale pesticide delivery system may find widespread application in the field of plant protection in the future.