Improved Biological Control of Bacterial Leaf Blight Using a Surfactant Complex of CO2 Micro-Nanobubbles Coated with Crude Ethyl Acetate Extract of Trichoderma polyalthiae UBZSN2-1

The bacterium <i>Xanthomonas oryzae</i> pv. <i>oryzae</i> is an important pathogen that causes wilt leaf blight disease in rice (<i>Oryza sativa</i> L.), leading to a reduction in rice yield. Therefore, this study aimed to investigate the potential of a surfactant complex composed of CO₂ nanobubbles (CO₂-NBs) coated with sorbitan monostearate (Sp60) and a crude extract of <i>Trichoderma polyalthiae</i> as active ingredient delivery agents for controlling leaf blight under both laboratory and greenhouse conditions. The addition of Sp60 and crude extract as surfactants significantly influenced the size uniformity and stability of CO₂-NBs at the nano level, with the nanobubbles remaining intact in water for up to 14 days. In addition, CO₂-NBs with crude extract and Sp60 reduced the severity of wilt, with an minimum inhibitory concentration (MIC) value of 64 µg/mL and an minimum bactericidal concentration (MBC) value of 128 µg/mL, and inhibited the disease by more than 50% in greenhouse conditions. Therefore, this study presents a creative and eco-friendly approach to managing bacterial leaf blight in rice that is innovative and relevant to sustainable plant protection.