Effect of Fipronil on Feeding,Pupation and Adult Emergence of 3rd Instar Larvae of Diamondback Moth,Plutella xylostella (Linnaeus)

Based on the indoor toxicity test of Fipronil to the 3rd instar larvae of diamondback moth(Plutella xylostella(Linnaeus)),the effect of Fipronil on feeding,pupation and adult emergence of the tested insect was studied.At the chosen concentrations,no effect on the average feeding amount either for the dead or survival individuals was found.The treatment of Fipronil at 0.20 mg/L could increase the total feeding amount of the tested insect by 22%,while the other treatments could decrease the total feeding amount and the highest decreased rate was 70% when Fipronil was at 12.5 mg/L.Besides,Fipronil treatment could reduce pupal weight a little and postpone pupation.The average pupation time in the check was 110 h,while that was 177.6 h when the insect was treated with Fipronil at 12.50 mg/L.