Biocidal activity of biosynthesized magnesium oxide nanoparticles derived from ginger (Zingiber officinale) against the saw-toothed grain beetle, Oryzaephilus surinamensis (Coleoptera: Silvanidae)

During the period of 28 July-4 August 2015, samples of rice seeds infected with the sawtoothed grain beetle Oryzaephilussurinamensis were collected from three sectors of Kirkuk city (Rahim Awa, Baghdad Road, and Domiz). The experiments were carried out in the laboratories of the College of Education for Pure Sciences, University of Kirkuk. Development of New Green MgO NPs Grown through Sustainable Methods Using Ginger Rhizome Extract (Zingiberofficinale) as a Reducing and Stabilizing Agent The obtained nanoparticles were characterized by XRD, UV–Vis, FTIR, TEM, and zeta potential analysis. It was then used to confirm the successful synthesis of the crystalline nanoparticles that were of nanoscale size and which displayed significant stability in solution. The biological activities of these nanoparticles were tested on sawtoothed grain beetle using three concentrations, namely 500, 1000, and 1500 ppm. Results indicated that with increasing concentrations, there was a significant reduction in the total egg counts laid as well as the numbers of emerged adults. Mean egg laying dropped from 389.67 eggs in the control treatment to 97.67 eggs at 1500 ppm of MgO NPs. In the same way, number of emerged adults were reduced from 312.33 insects in the control to 41.33 and 33.00 insects at the highest concentration of MgONPs, respectively.In addition, the treatments extended the incubation period of the eggs and the larval and pupal stage durations in comparison to the control, with significant increased mortalities observed in the latter cases (100% mortality achieved at 1500 ppm). These nanoparticles not only helped to decrease weight loss of seeds but also showed repellent effect for that insect, where the obtained highest repellency (40%) was found for MgO nanoparticles, at the highest concentration. In terms of rice seed germination, germination percentage remained relatively high after moderate concentrations in comparison with the control. Our findings suggest that the biosynthesized MgO NPs may constitute an efficient and environmentally friendly strategy for the control of sawtoothed grain beetle and its associated damage to stored grains.