Lethal And Sublethal Effects Of Novel Insecticides(Fluralaner And Broflanilide) To Tetranychus Urticae And Side Effect Of Broflanilide On Typhlodromips Swirskii

Farmers and growers of greenhouse and field crops face numerous species of polyphagous and phytophagous pests,including two-spotted spider mite(TSSM)Tetranychus urticae Koch(Acari:Tetranychidae).This species has become a harmful economic pest in many cultivated crops,and due to its rapid growth rate and rapid adaptation to numerous acaricides,its control poses severe threats to farmers.Therefore,this study aimed at identifying novel acaricides to avoid resistance build-up of the TSSM.Fluralaner and broflanilide are new kinds of novel insecticide with excellent activity against Lepidoptera insects.However,its activity and sublethal effects on TSSM is still unclear.Therefore,the effects of fluralaner and broflanilide on the sublethal activities to TSSM were determined.The study aims to provide scientific research for the application of fluralaner and broflanilide in the management of TSSM to reduce resistance.1.Lethal and sublethal effects,and insecticidal activity of fluralaner on TSSM Tetranychus urticaeThe lethal and sublethal activity of fluralaner on TSSM were surveyed in this research,and fluralaner exhibited higher activity towards TSSM female adults(LC50,0.49 mg L-1)and excellent activity towards eggs(LC50,0.36 mg L-1).The results of a sublethal effect study showed a significant reduction in the duration and fecundity of female adults in the tested concentrations.The net reproductive rate(R0)decreased to 67.34±3.96 and 50.29±3.40 offspring per individual in LC10 and LC30 treatments,respectively,compared with control(108.31 ±7.61 offspring/individual).The intrinsic rate of increase(r)and finite rate of increase(λ)in the controls(0.30 and 1.36 d-1)were significantly higher than those in the LC30 treatment(0.25 and 1.29 d-1);whereas,they were almost identical to values for the LC10 treatment.No change in mean generation time(T)was observed at sublethal concentrations treatments2.Lethal and sublethal effects insecticidal activity of broflanilide to TSSM and its side effect on Typhlodromips swirskiiThe toxicity of TSSM on broflanilide displayed not only excellent toxicity to TSSM eggs(LC50,1.015 mg·L-1),but also higher toxicity to adult females(LC50,2.062 mg·L-1).In contrast,the side effects of broflanilide to predatory mites Typhlodromips swirskii(Acari:Phytoseiidae)was lower than fenpyroximate and abamectin.In the sublethal study,a significant decrease in the female adult’s duration and fecundity was observed in LC10,and LC30 of broflanilide treated TSSM.The net reproductive rate(R0)decreased to 69.44±2.21 and 48.33± 1.75 offspring/individual in LC10 and LC30 treatments in comparison with the control(103.39±3.68 offspring/individual).The intrinsic rate of increase(r)and finite rate of increase(λ)in the control group(0.32 and 1.38 d-1)were significantly higher than those in LC30 groups(0.26 and 1.30 d-1),while LC10 showed almost the same value as the control group(0.30 and 1.34 d-1).No change in mean generation time(T)was observed in sublethal concentration treatments.