Evaluating the efficacy of a soil disinfection treatment for deep soil depth using dazomet combined with flooding against tomato bacterial wilt

Abstract

A combination treatment of dazomet with flooding was evaluated for its efficacy in soil disinfection of the deep layer. Following a typical treatment of dazomet (no flooding), the concentration of methylisothiocyanate (MITC) measured was very high in the plow layer, whereas it was below detection limits in the deep soil layer. On the other hand, a high concentration of MITC was detected in the deep soil layer when combined with flooding treatment. Using dazomet at a dose of 60 kg/10 a, tomato bacterial wilt (Ralstonia solanacearum) was well controlled, while a dose of 30 kg/10 a did not provide enough control. In an experiment in a severely infested plastic greenhouse in Hida-city, Gifu Prefecture, Japan, soil disinfection using dazomet reduced the percentage of wilted tomato (Solanum lycopersicum L.) plants to only 0%–2.8% when applied at 60 kg/10 a and combined with flooding, followed by planting tomato seedlings grafted onto highly resistant rootstocks. Our results indicate that the addition of a flooding treatment can transport dazomet deeper in the soil and improve the control of tomato bacterial wilt.