Toxicity of some nanomaterials against Botrytis allii, the causal pathogen of neck rot disease of onion (Allium cepa L.)

Abstract

In this study, 14 fungal isolates associated with symptomatic onion samples collected from different counties of Sohag Governorate showing neck rot disease were obtained and identified as Botrytis allii Munn (12 isolates) and B. cinerea Pers. (2 isolates). Pathogenicity tests carried out in the greenhouse showed that only isolates of B. allii were pathogenic to onion plants and caused identical neck rot symptoms among all fungal isolates tested. However, B. allii isolates exhibited different levels of virulence. Isolate No. 9 of B. allii was the high pathogenic one, where it caused 95 and 81.65% of disease incidence and severity, respectively. In vitro, the influence of carbon, MgO, and ZnO nanoparticles tested at 0.1, 0.2, and 0.3 mM on mycelial linear growth and biomass of B. allii was studied. Results obtained showed that all tested nanomaterials significantly reduced the mycelial linear growth and biomass at all concentrations tested. The nano MgO at 0.3 mM caused the high inhibitory effect followed by nano ZnO,