Determination of insecticidal activity of zinc oxide nanoparticles in khapra beetle Trogoderma granarium

Khapra beetle Trogoderma granarium Everts (Coleoptera: Dermestidae) is a major stored product pest worldwide. This pest negatively impacts the agricultural economy and inter-country trade due to the damages it causes on grains. Many of the methods used to control khapra beetle in recent years are harmful to nature and human health, because they contain chemical pesticides. Nanotechnology is an area that can bring innovation to various scientific fields. The synthesis of nanoparticles (NP) with the green synthesis method is a new environmentally friendly method, especially in which plants are used. Due to its insecticidal properties, the effectiveness of celery (Apium graveolens L. var. dulce) in controlling many harmful insects has been investigated. In this thesis, it was aimed to use Zinc Oxide (ZnO) NPs, which have low toxicity effect on human health and the environment, as a potential control tool against khapra beetle. The synthesis of ZnO NPs was carried out using celery plant extract without using any toxic solvents or chemical reducing agent. Characterization of synthesized ZnO NPs was performed with Emission Scanning Electron Microscopy (FESEM), UV-Vis Spectrophotometry (UV-Vis), X-Ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Zeta Potential Analyses. The effects of synthesized ZnO NPs on khapra larvae and adults were investigated through feeding experiments. In adults, the LC50 and LC90 values were determined at the end of the 48th and 96th hour following the application of 500 ppm concentration, respectively. The effect of ZnO NPs on Catalase (TgCAT), Heat Shock Protein 60 (TgHSP60), and Heat Shock Protein 68 (TgHSP68) genes was investigated at the molecular level using Quantitative Real Time PCR (RT-qPCR) in larvae and adults. In larvae, the highest expression of TgCAT, TgHSP60, and TgHSP68 was detected after 12 hours of ZnO NP exposure. In adults, the highest expression for three genes was observed after 144, 96, and 72 hours, respectively. According to the results of this study, it can be suggested that ZnO NPs can be used as an insecticidal agent in the control of khapra beetle. In addition, the investigated TgCAT, TgHSP60, and TgHSP68 genes have potential biomarker feature that can respond to oxidative stress caused by ZnO NPs.