Abstract
In hydroponic culture, the effects of biocontrol agents (BCAs) and lysine on bacterial wilt of tomato were examined using a pumice medium artificially infested with Ralstonia solanacearum. In small - pot experiments, the addition of lysine or lysine together with BCAs resulted in a remarkable reduction in the disease index of bacterial wilt. In a greenhouse experiment, while Pseudomonas fluorescens Me1RC2Rif did not decrease the disease index, no disease symptoms were observed when MelRC2Rif and lysine (1 mg g^<-1>) were added to the pumice medium, although the tomato yield decreased significantly. In the second year the amount of lysine was reduced to 0.25 mg g^<-1> and every two weeks, 0.25 mg g^<-1> of lysine was added together with Ralstonia pickettii K20. The disease index was significantly lower and the tomato yield was significantly higher in the K20, K20 + lysine and lysine treatments than in the control inoculated with only the pathogen. The quality of tomato, estimated based on the contents of sugar, lycopene and vitamin C, was not markedly different in the K20, K20 + lysine and lysine treatments from that in the control not inoculated with the pathogen.
