Evaluating the efficacy of anaerobic soil disinfection against soil-borne pathogens of tomato using sugar-containing diatomite and dried molasses

Abstract

An optimized method of anaerobic soil disinfestation (ASD) using sugar-containing diatomite or dried molasses was evaluated for efficacy against tomato bacterial wilt, tomato corky root, tomato bacterial canker, and root-knot nematode. The soil redox potential of both the diatomite and molasses treatments at a dose of 1 t/10 a was high at a soil depth of 40–50 cm (beyond the plowing depth). This indicates that the soluble carbon source in the treatments eluted and permeated into the deeper layer, leading to soil reduction. Populations of Ralstonia solanacearum and root-knot nematode decreased below the detection limit after ASD was completed. The occurrence of the four soil-borne pathogens monitored was not observed or was suppressed to low levels during tomato cultivation following ASD. In particular, protection against tomato bacterial wilt was enhanced by ASD, which was followed by the plantation of tomato seedlings grafted onto resistant rootstocks.