Retarded development of Verticillium wilt in eggplant after application ofBion (R) or Oryzalin (R)

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 mmo l/l Oryzalin(R) also delayed disease development whereas root application o f Bion(R) did not. Aerial applications of 0.1 and 0.2 mmol/l Bion(R) delaye d disease development in pot experiments. Oryzalin(R) was toxic at these co ncentrations. Each compound showed a weak activity over a narrow range of c oncentrations.