ZnO-based nanomaterials have high antifungal effects, such as inhibition of growth and reproduction of some pathogenic fungi, such as Fusarium sp., Rhizoctonia solani and Macrophomina phaseolina. Therefore, we report the extracellular synthesis of ZnONPs using a potential fungal antagonist (Trichoderma harzianum). ZnONPs were then characterized for their size, shape, charge and composition by visual analysis, UV–visible spectrometry, X-ray diffraction (XRD), Zeta potential, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). The TEM test confirmed that the size of the produced ZnONPs was 8–23 nm. The green synthesized ZnONPs were characterized by Fourier transform infrared spectroscopy (FTIR) studies to reveal the functional group attributed to the formation of ZnONPs. For the first time, trichogenic ZnONPs were shown to have fungicidal action against three soil–cotton pathogenic fungi in the laboratory and greenhouse. An antifungal examination was used to evaluate the bioactivity of the mycogenic ZnONPs in addition to two chemical fungicides (Moncut and Maxim XL) against three soil-borne pathogens, including Fusarium sp., Rhizoctonia solani and Macrophomina phaseolina. The findings of this study show a novel fungicidal activity in in vitro assay for complete inhibition of fungal growth of tested plant pathogenic fungi, as well as a considerable reduction in cotton seedling disease symptoms under greenhouse conditions. The formulation of a trichogenic ZnONPs form was found to increase its antifungal effect significantly. Finally, the utilization of biocontrol agents, such as T. harzianum, could be a safe strategy for the synthesis of a medium-scale of ZnONPs and employ it for fungal disease control in cotton.

Mycogenic silver nanoparticles (AgNPs) produced by some biocontrol agents have shown the ability to inhibit the growth of numerous plant pathogenic fungi, which may be a unique method of disease management. This study describes the extracellular production of AgNPs by Trichoderma harzianum. The size, shape, charge, and composition of the AgNPs were subsequently studied by UV-visible spectroscopy, DLS, zeta potential, TEM, SEM, and EDX, among other methods. The AgNPs had sizes ranging from 6 to 15 nm. The antifungal activities of bio-synthesized AgNPs and two commercial fungicides (Moncut and Maxim XL) were tested against three soil-borne diseases (Fusarium fujikuroi, Rhizoctonia solani, and Macrophomina phaseolina). Cotton seedling illnesses were significantly reduced under greenhouse settings after significant in vitro antifungal activity was documented for the control of plant pathogenic fungi. The use of biocontrol agents such as T. harzianum, for example, may be a safe strategy for synthesizing AgNPs and using them to combat fungus in Egyptian cotton.

For this study, samples were collected from seedlings infected with damping-off or root rot in adult cotton plants from different locations in the Giza governorate. The samples yielded 25 fungal isolates. The isolates were identified as (44%) Rhizoctonia solani (44%), Fusarium spp. (44%) and Macrophomena phasolina (12%). In the pre-emergence stage of the cotton seedlings, 24 fungal isolates were pathogenic on cultivar Giza 90, while all fungal isolates were pathogenic on Giza 94 compared to the control. On Giza 90, F. fujikuroi F10 (80%), R. solani RS9 (100%), M. phasolina M4, and M12 (34%) were the most pathogenic isolates. On Giza 94, F. fujikuroi F10 (100%), R. solani RS9 (100%), M. phasolina M4 (64%) were the most pathogenic isolates. In the post-emergence stage of Giza 90, Fusarium isolate F1 (22%), R. solani RS11 (18%), M. phasolina M4, and M12 (48%) were the most pathogenic isolates. On Giza 94, Fusarium isolate F1 (16%), R. solani RS4 (14%), and M. phasolina M4 (24%) were the most pathogenic isolates. All isolates were pathogenic and decreased the survival percentage of the two cultivars. On Giza 90, F. fujikuroi F10 (0%), R. solani RS9(AG2-2) (0%), and M. phasolina M4 (18%) were the most effective isolates in decreasing survival. On Giza 94, F. fujikuroi F10 (0%), R. solani RS9(AG2-2) (0%) group, and M. phasolina M4 (16%) were the most effective isolates in decreasing survival. The most effective fungal isolates that decreased plant height and dry weight for both cultivars were F. fujikuroi F10, RS9(AG2-2), and M4.