Report on the occurrence of shiso mosaic disease and on-farm research for efficient disease control in the Aichi prefecture

Abstract

In this study, the occurrence of perilla mosaic disease in Aichi prefecture, Japan, was evaluated by conducting a questionnaire survey among perilla farmers. About 90% of the farmers reported the occurrence of this disease in their crop, while about 30% reported the disease to have affected over 10% of their cultivation facility. The survey results suggested that the risk of disease development was significantly increased when perilla was planted in the field around the cultivation facility. In the local cultivation facility, we performed cultivar control by removing infected perilla planted in the field that had been the source of this disease during the cultivation period in summer 2016. As a result, the rate of this disease decreased compared with that during the cultivation in summer 2015, when no control measures were implemented. In addition, it was revealed that disease in the cultivation facilities was more often reported near the side windows, with higher incidences occurring from July to November. During the cultivation in summer 2017, after removing the source of infection and properly applying pesticide spray from July to November, the rate of the occurrence of perilla mosaic disease decreased further compared with that during the cultivation in summer 2016.