Abstract
Leaf spot and blight symptoms caused by Alternaria alternata have been widely occurred on tomatoes and potatoes in Egypt. In attempts to improve the sustainability of crop protection, the use of nanotechnology in producing nano-fungicides as an eco-friendly convenient approach was needed to control such diseases. Titanium dioxide nanoparticles (TiO(2)NPs) and Silver nanoparticles (AgNPs) were biosynthesized by Aspergillus versicolor KY509550 through surface resonance peaks at 340 and 400 nm, respectively. The preparation of Selenium nanoparticles (SeNPs) was done using glucose solution method at 387 nm. The sizes of the prepared nanoparticles were 47.15, 36 and 78 nm for TiO(2)NPs, AgNPs and SeNPs, respectively. It was detected from Transmission Electron Microscope (TEM) analysis that TiO(2)NPs and AgNPs were well dispersed in the solution without any agglomeration compared with SeNPs. The antifungal activity of TiO(2)NPs, AgNPs and SeNPs at three concentrations viz.50, 75 and 100 ppm were estimated against A. alternata by laboratory trials. The biosynthesized TiO(2)NPs exhibited the highest inhibitory effect at100 ppm against A. alternata and in turn resulted in 90% decrease of its mycelial growth in vitro trials. The greenhouse and field trials explored also that TiO(2)NPs was significantly effective in reducing disease severity (DS) as shown by the calculated area under disease progressive curve (AUDPC). SeNPs revealed close results to that obtained by TiO(2)NPs for both trials. AgNPs showed a moderate effect at the tested concentrations in all trials. Nanoparticles could be powerful and eco-friendly nano-fungicides for biological control of tomato leaf blight.