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

A peroxyacetic acid mixture (CH 3 CO 3 H) 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.