RESUMO
AIMS: Because of severe economic losses and food security concerns caused by plant pathogenic bacteria, Ralstonia solanacearum, there is a need to develop novel control methods. This study was aimed to green synthesize the zinc oxide nanoparticles (ZnO NPs) through Withania coagulans leaf extracts and checked their antibacterial potential alone or in combination with W. coagulans leaf extract for the management of R. solanacearum causing bacterial wilt disease in tomato. METHODS AND RESULTS: ZnO NPs were synthesized through an eco-friendly approach using leaves extract of W. coagulans and characterized through various spectroscopic approaches, that is Fourier transform infrared spectroscopic, UV-visible spectroscopy and energy dispersive spectroscopy. The antibacterial effect of W. coagulans leaf extract and ZnO NPs alone and in combination was tested in vitro and in vivo against bacterial wilt pathogen in tomato plants. The results showed that combine application of leaf extract and ZnO NPs inhibited in vitro growth of R. solanacearum more than applying alone. Three application times (0, 6 and 12 days before transplantation) of leaf extract, ZnONPs and their combine application were tested in vivo. The combine treatment and longest application time (12 days before transplantation) were more effective in suppressing soil population of R. solanacearum, reducing disease severity and enhancing plant growth than applying alone and smaller application time. CONCLUSION: It is concluded that W. coagulans leaf extract and ZnO NPs have strong antibacterial potential against R. solanacearum in vitro and in vivo. SIGNIFICANCE AND IMPACT OF STUDY: The results of this study suggest the potential application of leaf extract and ZnO nanoparticles for controlling R. solanacearum as safe, eco-friendly and less expensive integrated disease management strategy in tomato crop.