2003 Volume 2 Issue 3 Pages 215-219
Effects of a newly developed sterilizing system using TiO2 photocatalysis on the suppression of tomato root rot disease in nutrient solution were evaluated. The germination rate of Fusarium oxysporum micro-conidia was suppressed to nearly zero when 100 liter of infested water was passed through the sterilizing system at flow rate of between 5 and 20 liter/min for 90 min. The germination rate of Pythium aphanidermatum zoospores was suppressed to nearly zero when 30 liter of infested water was passed through the system at flow rates of 5 and 10 liter/min for 10 and 60 min, respectively. In the solution culture of tomato seedlings, this sterilizing system could delay the outbreak of Pythium root rot by 2-3 days compared with the control. The tops of the tomato plants showed chlorosis and the TiO2 surface became brown at the end of experiment, suggesting that there was an Fe deficiency in the plants. The concentrations of Fe and Zn in the nutrient solution rapidly decreased soon after sterilization of the nutrient solution was initiated. The current sterilizing system using TiO2 photocatalysis requires further improvement for practical use.
