Abstract
This investigation assessed the insecticidal efficacy of two graphene formulations (Gr1 and Gr2) on wheat kernels against adults of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) in relation to temperature and relative humidity (RH) at concentrations of 500 and 1000 ppm. These bioassays were conducted in all possible combinations of three temperature levels: 20, 25, and 30 °C, as well as two relative humidity levels (55 and 75%). Progeny production was also evaluated 65 days later. The species that emerged as the most susceptible to graphene-treated wheat kernels was O. surinamensis compared to S. oryzae , regardless of temperature, RH, dose, and graphene formulation. At high RH levels, increasing temperature led to a decrease in mortality of S. oryzae in both Gr1 and Gr2, whereas at low RH levels, the results were dependent on the dosage of graphene formulation. At 75% RH, mortality ranged at significantly lower rates compared to their corresponding ones at 55% RH, while RH appeared to have no effect at 20 °C regardless of graphene formulation. Total inhibition of the emergence of progeny production was recorded for O. surinamensis , while graphene failed to suppress the progeny of S. oryzae. The current study’s findings offer evidence supporting the feasibility of using graphene as an alternative to chemical-based pest control approach for protecting grain stored products.