Efficacy Assessment of Biosynthesized Copper Oxide Nanoparticles (CuO-NPs) on Stored Grain Insects and Their Impacts on Morphological and Physiological Traits of Wheat (Triticum aestivum L.) Plant

SIMPLE SUMMARY: In the current study, copper oxide nanoparticles (CuO-NPs) were successfully formed through the reduction of CuSO(4)·5H(2)O by the activity of Aspergillus niger strain (G3-1) metabolites. The as-formed CuO-NPs were characterized by UV–visible (UV–vis) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy–energy dispersive spectroscopy (SEM-EDX), Fourier-transform infra-red (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Data showed the efficacy of fungal metabolites to fabricate crystallographic, spherical CuO-NPs with sizes of 14.0 to 47.4 nm at varied bending energies. The biosynthesized CuO-NPs exhibited activity against two wheat grain insects, Sitophilus granarius and Rhyzopertha dominica, in a size- and dose-dependent manner. Moreover, the lower CuO-NP concentrations had beneficial effects on the morphological and physiological aspects of wheat plants, without displaying any toxicity or repression of growth. ABSTRACT: Herein, CuO-NPs were fabricated by harnessing metabolites of Aspergillus niger strain (G3-1) and characterized using UV–vis spectroscopy, XRD, TEM, SEM-EDX, FT-IR, and XPS. Spherical, crystallographic CuO-NPs were synthesized in sizes ranging from 14.0 to 47.4 nm, as indicated by TEM and XRD. EDX and XPS confirmed the presence of Cu and O with weight percentages of 62.96% and 22.93%, respectively, at varied bending energies. FT-IR spectra identified functional groups of metabolites that could act as reducing, capping, and stabilizing agents to the CuO-NPs. The insecticidal activity of CuO-NPs against wheat grain insects Sitophilus granarius and Rhyzopertha dominica was dose- and time-dependent. The mortality percentages due to NP treatment were 55–94.4% (S. granarius) and 70–90% (R. dominica). A botanical experiment was done in a randomized block design. Low CuO-NP concentration (50 ppm) caused significant increases in growth characteristics (shoot and root length, fresh and dry weight of shoot and root, and leaves number), photosynthetic pigments (total chlorophylls and carotenoids), and antioxidant enzymes of wheat plants. There was no significant change in carbohydrate or protein content. The use of CuO-NPs is a promising tool to control grain insects and enhance wheat growth performance.