Persian Journal of Acarology

Abstract Recently, using eco-friendly controlling methods against pests has been getting great attention. Therefore, this study aimed to assess synthesis of two different phases of nano aluminum oxide, alpha and Gamma, (α- and γ-Al₂O₃ NPs) from wastes. Additionally, evaluate them to control stored product mites, Mycetoglyphus fungivorus, and Caloglyphus mycophagus, and the fungi Aspergillus flavus, Alternaria sp., and Fusarium oxysporum. Two phases of Al₂O₃ NPs were synthesized in acidic and basic media and characterized using the field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), ultraviolet-visible (UV-Vis) and thermo gravimetric analysis (TGA). Mortality percentages of mites were evaluated at concentrations of 10, 30 and 60 ppm after 1, 2, 3 and 4 days. The growth of fungi was assessed to determine the fungicidal concentrations in PDB cultures by Mycelium Dry Weights Method. The study confirmed the formation and thermal stability of α- and γ-Al₂O₃ NPs using FESEM, UV-Vis and TGA. The average particle size of α-Al₂O₃ is 4–10 nm and for γ- Al₂O₃ is 14–30 nm. Both phases were toxic to tested stages of mites. Increasing concentration and exposure time, results in increased mite mortality rates. γ-Al₂O₃ NPs were more efficient than α-NPs post initial exposure, then all through time both have the same effect. The female's fecundity was significantly influenced. Tested eggs did not hatch at all. The toxic activity remained strong after 1, 2, and 3 months of exposure. The SEM images revealed a strong adhesive of α- and γ-NPs which were visibly bonded to various areas of dead mite females. γ-Al₂O₃ showed antifungal activity more than the α-NPs. Concentrations of fungicides depended on the fungal strain sensitivity. It has been concluded that α- and γ-Al₂O₃ NPs are efficient environmentally friendly agents against the proliferation of storage mites and mycotoxin producing fungi.

Abstract The objectives of this study were to investigate the population fluctuation of Tetranychus urticae Koch (Acari: Tetranychidae) on three Capsicum annuum L. (Solanaceae) cultivars (red delta star, yellow delta star and chili omega 62). Experimental trials were carried out under high plastic-net house conditions during two seasons, 2021–2022 and 2022–2023. The feeding effects of T. urticae on some biochemical compounds of C. annuum were estimated. Densities of egg and mobile stages on the three test cultivars increased gradually from initial count in March 15^th and reached peak at last week of November of two seasons, except densities of eggs on red delta reached peak at last week of October. In both growing seasons, the highest population densities of T. urticae were observed on red delta star, while the lowest densities were on chili omega 62. Correlation coefficient of T. urticae densities levels with total carotenoids, carbohydrates and proteins of tested C. annuum cultivars showed positive relationship and a reverse one with total lipids, chlorophyll, phenolic, flavonoids and alkaloids compounds.