Ultrafine Bubble Water for Crop Stress Management in Plant Protection Practices: Property, Generation, Application, and Future Direction

Every year, up to 40% of the crops in the world are lost to pests. Plants have suffered from prolonged biotic stresses and abiotic stresses, which cause significant changes in complex crop ecosystems, necessitating intensive pest management strategies that have often been accompanied by the struggle against plant pests. Plant pests and diseases control methods heavily reliant on chemical pesticides have caused many adverse effects. One innovative method involves using ultrafine bubble (UFB) waters, which can enable 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 pests and the soilborne, airborne and waterborne diseases were analyzed, and the abiotic stresses of crops in high-salinity soil and contaminated soil, drought, and soil with heavy metals were reviewed. Despite promising applications, UFB technology has limitations. Aiming at pesticide reduction and replacement using UFB waters, 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 an integrated intelligent crop growth system were proposed.