Sublethal Effect Of Two Insecticides On Myzus Persicae Sulzer

Potato is the fourth largest food crop in the world,and also an important global food source.The negative consequences of diseases and pest greatly affects its sustainable production.Myzus persicae?Sulzer?is one of the most important pests of potato,which cause major damage to potato plants through feeding and transmission of viruses.Presently,the control of M.persicae mainly depends on chemical insecticides,which can cause environmental pollution,pesticide residues in food and agricultural products and sublethal effect on some agricultural important insect.The study of sublethal effect is an important aspect of insecticide control.In this experiment,nine kinds of insecticides were used to determine their virulence to M.persicae using"Longshu No.3"potato as the host plant.The main results are as follows:1.Determination of virulence and sublethal dose of 9 insecticides to M.persicae on potatoThe nine kinds of insecticides had great toxicity to M.persicae The toxicity of 3.15%Avermectin·Imrdacloprid?EC?and 5%Beta cypermethrin?ME?were highly effective on M.persicae compare with the other pesticides,with LC₅₀ value of 0.7304 mg/L and 0.8731mg/L,respectively.The second highest toxicity occurred in 33%Beta cypermethrin·Imidacloprid?SC?,3.2%Avermectin?EC?and 9%Beta cypermethrin?SC?,with LC₅₀ values of 1.3849 mg/L,1.8553 mg/L and 2.6607 mg/L,respectively.The following three insecticides were 22%Sulfoxaflor?SC?,30%Thiamethoxam?SC?and 20%Clothianidin?SC?,with LC₅₀ values of 5.7828 mg/L,5.8653 mg/L and 6.2793 mg/L,respectively.The toxicity of 20%Imidacloprid?SL?was the least,with the LC₅₀ value of22.8952 mg/L.2.Effects of two insecticides on life table parameters of M.persicae on potatoThe sublethal concentrations LC₁₀,LC₂₅ and LC₄₀ of Avermectin and Avermectin·Imidacloprid significantly reduced the mean longevity and fecundity of F₀generation of M.persicae on potato.After LC₄₀ treatment,the mean longevity and fecundity of F₀ generation were 10.68 and 8.07 days,and 17.05 and 9.52 respectively.The sublethal dose had a significant linear correlation with the mean longevity and fecundity of F₀generation.Different sublethal concentrations of the two insecticides significantly prolonged the Period of F₁ generation of M.persicae on potato,and significantly shortened the Adult stage and the Nymphal to adult.The whole generation of F₁ generation of M.persicae was the shortest after LC₄₀ treatment,which is 18.65 and 18.37 days.Compared with the control,the survival rate and fecundity of F₁ generation decreased significantly from the 8th day.The Net reproductive rate?R₀?,Intrinsic rate of increase?r_m?and Finite rate of increase???of F₁ generation also decreased significantly,and the Doubling time?Dt?prolonged significantly.The two insecticides effectively controlled the population growth of M.persicae on potato.3.Effects of two insecticides on the important target enzymes and detoxification enzymes of M.persicae on potatoThe sublethal concentrations LC₁₀,LC₂₅ and LC₄₀ of Avermectin and Avermectin·Imidacloprid affected the activities of Ach E and Car E,GST,MFO in the body of M.persicae on potato.The target enzyme Ach E was induced to increase the activity at6-12 h,and the detoxification enzyme GST,MFO and Car E were induced to increase the activity at 0-6,6-12 and 12-24 h,respectively.It is speculated that the detoxification enzyme has synergistic effect in the detoxification process of insecticides.