Effect of a peroxyacetic acid mixture as green chemical on rice bacterial and fungal pathogens

Abstract

A peroxyacetic acid mixture (CH3CO3H) has been used as a disinfectant for a low environmental impact. In this study, we investigated whether a commercial peroxyacetic acid mixture, Perosan, can be applied as a green chemical to control bacterial and fungal pathogens, Xanthomonas oryzae pv. oryzae (Xoo) and Rhizoctonia solani in rice plants. Paper discs carrying 25% Perosan caused obvious chlorosis on rice leaves. Ion leakage caused by the phytotoxicity was obviously observed at 5% and higher concentrations of Perosan. Perosan treatment resulted in a slightly decreased pH in rice growing water. In a bacterial growth inhibition assay using optical density measurements, 0.007% of Perosan almost completely inhibited the Xoo growth for 36 h. In an agar dilution assay for antifungal activity, mycelial growth inhibition of R. solani was observed with 0.05% addition of Perosan. In planta antimicrobial activity assay with 5% of Perosan inhibited the lesion lengths in Xoo-inoculated rice plants. A spray of 0.5% Perosan significantly inhibited the lesion developments on the leaves inoculated with an agar disc of R. solani. Our results suggest that Perosan can be applied to rice plants to control the pathogens, Xoo and R. solani, as a green chemical.