Clarification of the necessary meteorological conditions to control Ralstonia solanacearum via soil solarization

Abstract

The present study was conducted to investigate the relationships between meteorological conditions and the disinfection effect of soil solarization in five greenhouses (located in Kaizu City, Gifu, Japan). The specific analysis focused on soil temperature, the population density of Ralstonia solanacearum before and after soil disinfection, the air temperature inside and outside the greenhouse, the amount of solar radiation, and rainfall. The density of R. solanacearum decreased markedly after soil solarization with the average daily soil temperature exceeded 40 °C for 10 consecutive days or more. In the scope of this study, the meteorological conditions required to meet this condition included: a disinfection period of 24 days or more, an average daily air temperature above 28.0 °C, as well as average daily solar radiation exceeding 17.0 MJ m−2. Moreover, with the average daily soil temperature of the soil surface layers exceeded 40 °C for 10 consecutive days or more, the average daily air temperature and average daily solar radiation should be higher than 29.3 °C and 20.2 MJ m−2, respectively. If the mentioned meteorological conditions were met, a fairly good disinfection effect could be achieved. However, if the greenhouse was poorly insulated, or if the solar radiation and air temperature decreased significantly in rainy and cloudy days, the soil was not likely to reach 40 °C or more for 10 consecutive days.