Insectificial and insecticide effects of essential oil and powder of orange peels on <i>sitophilus zeamais motsch</i>, a stock depreciator of corn (<i>zea mays</i>)

Post-harvest losses in maize stocks are caused by stock predators including Sitophilus zeamais. This work aimed to evaluate the insecticidal and insect repellent effects of orange peel powder and essential oil on this stock pest of maize (Zea mays) in order to contribute to food safety and security. The essential oil and orange peel powder, obtained by hydrodistillation and grinding orange peels respectively, were tested on S. zeamais adults from one generation of laboratory rearing. Experiments were carried out using different doses of powder and oil to study insect repellency and mortality as a function of dose and time. The results of the bioconservative insect repellency tests showed that the powder and essential oil were 100% repellent to S. zeamais within 7 hours and 4 hours, respectively. Moreover, these bioconservatives are potent insecticides, with 95% lethal doses (LD95) of 19.965±0.064 g/kg for the powder and 22.963±0.105 µl/kg for the essential oil. The results obtained indicate that orange peel powder and essential oil can be used to protect maize stocks against S. zeamais.