Biological Synthesis of Silver Nanoparticles Exposed to Gamma Irradiation for Control of Early Blight Disease in Tomatoes

Early blight disease causes a significant loss in tomato production. This study focuses on the effective suppression of Alternaria solani, which causes huge losses in tomato yield. The study was conducted at a nuclear research center in Egypt. Infected plants were treated with irradiated and non-irradiated silver nanoparticles.The fungiced Mancozeb was used as a positive control. Three sprays were carried out at 10-day intervals. Two biological agents, Alternaria alternata and Fusarium oxysporum, were used to produce silver nanoparticles. AgNPs were exposed to several doses of gamma radiation (0, 1.5, 3, 6, 12 and 24 kGy) in order to enhance and maximize the effect of AgNPs on Alternaria solani. U.V., DLS, FITR, and TEM were used to characterize AgNPs, and AgNPs + gamma irradiation. Gamma irradiation decreased the size of AgNPs. All treatments, particularly AgNPs supported by gamma irradiation, reduced disease severity when compared to the untreated control. The highest shoot fresh weight was recorded in A. alternata AgNPs +3 kGy; 174.38 g as the mean of two seasons. The highest shoot dry weight was obtained by A. alternata AgNPs +24 kGy with a mean of 151 g. All treatments elevated peroxidase and catalase as well as total chlorophyll as compared with the untreated control and healthy plant. AgNO3 decreased the efficacy of peroxidase (5). Alternaria alternata exhibited the lowest efficacy of catalase (9.09) after healthy plants and control. F. oxysporum + 24 kGy and A. alternata AgNPs + 24 kGy achieved the highest reduction of the mycelial growth in vitro