PROBLEM TO BE SOLVED: To prevent onion from becoming infected with downy mildew in onion cultivation.SOLUTION: In the method of growing onions of the present invention, onions are cultivated using ozone water or oxygen water in which ozone or oxygen is mixed in water. In particular, ozone water or oxygen water is generated by mixing ozone or oxygen into agricultural water, and the ozone water or oxygen water is sprayed on an onion seedling box or soil or leaves in a field. In addition, ozone or oxygen water is generated by mixing ozone or oxygen into agricultural water, and the ozone water or oxygen water is sprayed on onion leaves infected with downy mildew caused by Peronospora destructor.SELECTED DRAWING: NoneCOPYRIGHT: (C)2020,JPO&INPIT【課題】タマネギの栽培においてタマネギがベト病に感染してしまうのを防ぐこと。【解決手段】本発明では、タマネギの栽培方法において、水にオゾン又は酸素を混入させたオゾン水又は酸素水を用いてタマネギを栽培することにした。特に、農業用水にオゾン又は酸素を混入させてオゾン水又は酸素水を生成し、そのオゾン水又は酸素水をタマネギの苗箱又は圃場の土や葉に散布することにした。また、農業用水にオゾン又は酸素を混入させてオゾン水又は酸素水を生成し、そのオゾン水又は酸素水を、ペロノスポラデストラクター（Ｐｅｒｏｎｏｓｐｏｒａ ｄｅｓｔｒｕｃｔｏｒ）を原因菌とするベト病（露菌病）に感染したタマネギの葉に散布することにした。【選択図】なし
