Abstract:Bioassay of PoNPV+1%VBL, PoNPV+12.5 μL·L-1 Chlorbenzuron, PoNPV+15 μL·L-1 Trichlorphon was conducted on 2-instar larvae of Parocneria orientia in lab. The results showed that 1%VBL, 12.5 μL·L-1 Chlorbenzuron, 15 μL·L-1 Trichlorphon had better synergistic effect. Spraying of PoNPV+1%VBL, PoNPV+12.5 μL·L-1 Chlorbenzuron, PoNPV+15 μL·L-1 Trichlorphon and PoNPV to control 2 - 3 instar larvae of second generation in field, the concentrations of PoNPV were 8×106 PIB·mL-1, 4×106 PIB·mL-1, 2×106 PIB·mL -1, 1×106 PIB·mL -1, 5×105 PIB·mL -1, there were 20 treatments. It was indicated that when the concentration was the same, the effect of PoNPV added synergists was better than that without synergists.