Evaluating the Control Potential of Silicon Dioxide Against Xanthomonas phaseoli pv. phaseoli in Beans

The aim of this study was to investigate the potential of silicon (Si) applied to leaves and roots in controlling common bacterial blight disease caused by Xanthomonas phaseoli pv. phaseoli (Xpp), a significant bacterial pathogen of beans. Silicon dioxide (SiO₂) was applied at concentrations of 30 mM and 15 mM using two methods: (i) foliar spraying and (ii) root drenching. Phaseolus vulgaris cv. Gina was grown in a soilless substrate-based system. The application method of SiO₂ had a significant impact on disease severity. Foliar applications of SiO₂ did not influence disease development. However, root applications reduced disease severity by 44% and 62% at 15 mM and 30 mM doses, respectively, compared to the Xpp -inoculated control group. SiO₂ foliar applications had no significant effect on shoot fresh and dry weight or leaf number (LN) at either dose compared to the negative control (NC). However, root application of 30 mM SiO₂ significantly increased LN. Despite these findings, neither application method nor dose created a notable difference in plant growth parameters under disease pressure. In conclusion, SiO₂ must primarily be applied to the root system to exert its disease-suppressing effect. This positive impact appears to be independent of plant growth parameters. These findings suggest that SiO₂ root application holds significant potential for controlling common bean blight caused by Xpp in the context of sustainable agriculture.