Review and Prospects on Ultrafine Bubble (UFB) Water for Managing Crop Stresses in Plant Protection Practices

Plants are subjected to long-term biotic stresses and abiotic stresses which cause sig-nificant changes in complex crop ecosystems and have been often accompanied by the struggle against plant pests. Pests control methods relying heavily on chemical pesti-cides have resulted in numerous adverse effects. One of innovative methods involves using ultrafine bubble (UFB) waters may realize the pesticide reduction action for the plant pest control. The classification and six properties of UFBs were summarized, and the generation approaches of UFBs were introduced based on physical and chemical methods. The applications of UFBs and ozone UFB waters in plant protection practices were comprehensively reviewed, in which, UFB waters against the plant pest insects and the soilborne, airborne and waterborne diseases were analyzed, and the abiotic stresses of crops in salinity soil and contaminated soil were reviewed. Because UFB water is not omnipotent, several prospects were proposed aiming at pesticide reduc-tion and replacement, for example, the mechanism of UFB water controlling plant pests and diseases, the molecular mechanism of UFB water affecting plant pest resistance, the plant growth in harsh polluted environments, the UFB behavior with hydrophobic and hydrophilic surfaces of crops and the building of integrated intelligent crop growth system.