Retarded development of Verticillium wilt in eggplant after application of Bion or Oryzalin

Effects on root infection of eggplant caused by the soil-borne pathogen V. dahliae after application of the synthetic inducer Bion(R) or the herbicide Oryzalin(R) were investigated. Aerial application of 0.0125 and 0.025 mmol/l Bion(R) or 0.05 mmol/l Oryzalin(R) delayed disease development in Petri dish experiments. In Petri dish experiments, root application of 0.0125 mmol/l Oryzalin(R) also delayed disease development whereas root application of Bion(R) did not. Aerial applications of 0.1 and 0.2 mmol/l Bion(R) delayed disease development in pot experiments. Oryzalin(R) was toxic at these concentrations. Each compound showed a weak activity over a narrow range of concentrations.