The effectiveness of AgNPs synthesized using Aspergillus floccosus for controlling Phoma herbarum and Aphis Pomi de Geer

This study was conducted to synthesise silver nanoparticles (AgNPs) using Aspergillus floccosus fungal extract and to evaluate the pesticidal efficacy of the resulting nanopesticide product against two harmful organisms (pathogenic fungus and pest) affecting apples. The synthesised AgNPs were subjected to a series of characterisation tests (UV-Vis, FTIR, XRD, SEM, TEM, EDX, Zeta Potential) and, based on the results obtained, the AgNPs synthesis was successfully completed. Within the scope of this study, the first registration process has been carried out for the fungal pathogen (Phoma herbarum) that causes rot disease in apple fruits. The fungicidal efficacy of five concentrations of AgNPs (10, 25, 50, 100, and 200 mg L⁻¹) was evaluated against this pathogen under both in vitro and in vivo conditions. The results showed that AgNPs exhibited a significant inhibition on the mycelial growth of Phoma herbarum in vitro. The 200 mg L⁻¹ concentration showed the highest inhibition percentage (81.5%). Concerning in vivo test, the effect of AgNPs on disease severity index of Phoma herbarum in apple fruits was evaluated. The result of this part showed that the concentration 200 mg L⁻¹ of AgNPs exhibits highest fungicidal efficacy disease reduction rates (100%), Following by 67% for AgNPs 100 mg L⁻¹. The insecticidal effects of AgNPs on fourth-stage nymphs and adults of the pest (Aphis pomi) were evaluated in laboratory and field applications. For this purpose, AgNPs prepared at five different concentrations (30, 60, 90, 120, and 150 mg L⁻¹) were sprayed on the pests. The results showed that the insecticidal efficacy of AgNPs against Aphis pomi was directly related to both the dose and the exposure time. Specifically, the lethal concentration required to kill adults (LC50: 48.9 mg L⁻¹ for laboratory application and 68.4 mg L⁻¹ for orchard application) was higher than the dose required for nymphs (LC50: 32.3 mg L⁻¹ for laboratory and 52.1 mg L⁻¹ for orchard application). A similar trend was observed for lethal time, with adults exhibiting longer required exposure times (LT50: 51.2 h in the lab and 58.4 h in the orchard) compared to nymphs (LT50: 42.0 h in the lab and 45.1 h in the orchard). According to the results obtained, AgNPs synthesised using Aspergillus floccosus fungus have been proven to be highly effective at low doses against two major harmful organisms that cause qualitative and quantitative losses in apples. In conclusion, it has been proven that this silver-based nano pesticide product can be used as an alternative and innovative product in combating factors that cause agricultural damage to protect apple health.