Sensitivity Of Citrus Psyllid Field Population To Insecticides And The Development Of Pesticides Selected Kits

The citrus psyllid,Diaphorina citri Kuwayama（Hemiptera:psyllidae）.Its host plants both are rutaceae.The citrus psyllid is a vector of citrus Huanglongbing（HLB）,a destructive disease for citrus,as there is no chemical or other control method currently available that can completely cure the disease.Control of the population of the citrus psyllid is an important measure to inhibit the spread of the disease.Using pesticides to control the D.citri is a quick and effective method,However,lots of unreasonable,unscientific and groundless chemicals to control D.citri for a long time have led to different level of resistance.In order to improve the chemical more targeted,scientific and efficient control of D.citri,in this paper the sensitivity of chemicals for controlling D.citri adults and nymphs were research,high-efficiency chemicals were screened out can reduce the use of chemicals.And a pesticides selection kit for rapid detection of insecticide resistance in D.citri was developed hope that be more targeted and effective in chemicals use.In this paper,the enzyme activities of different D.citri populations were determined by biochemical methods,and the accuracy of the discriminating dose of the pesticide selection kit was verified by biochemical methods to further understand the biochemical mechanism of the insecticides resistance of D.citri.The main results are as follows:（1）The contact toxicity of D.citri adults showed that thiamethoxam was the most toxic to nicotine,with LC₅₀ value of 0.29mg/L;The order of toxicity is thiamethoxam>imidacloprid>acetamiprid.Among the pyrethroids,lambda-cyhalothrin has the strongest toxicity of citrus psyllid,with LC₅₀ value of 0.21 mg/L;The toxicity of deltamethrin to D.citri is relatively weak,LC₅₀ value is 0.98mg/L,and the order of toxicity is high-efficiency-cyhalothrin>bifenthrin>deltamethrin.In organophosphorus pesticides,the order of toxicity is chlorpyrifos>quinalphos.The contact toxicity of nymph showed that thiamethoxam had the strongest toxicity to nymph of D.citri,LC₅₀ value was 0.24mg/L,and the order of toxicity was thiamethoxam>imidacloprid>acetamiprid.Among the pyrethroids,bifenthrin has the strongest toxicity to D.citri,with LC₅₀ value of 0.35 mg/L.deltamethrin has a relatively weak toxicity to D.citri,with LC₅₀ value of 0.64 mg/L.the order of toxicity is bifenthrin>lambda-cyhalothrin>deltamethrin.Among organophosphorus pesticides,chlorpyrifos>quinalphos.（2）Diagnostic dose values of nine different insecticides are:imidacloprid:300mg/L;Thiamethoxam:200mg/L;Acetamiprid:700mg/L;Pyriproxyfen:800mg/L;Bifenthrin:40mg/L;High-efficiency-cyfluthrin:70mg/L;Deltamethrin:150mg/L;Chlorpyrifos:1900mg/L;Quinalphos:2100mg/L.Under different temperature preservation conditions,the kit can be preserved for one month and has no effect.And use of the kit at normal temperature has no effect.The bioassay and diagnostic dose method were used to determine the resistance evaluation standard of D.citri population in the same state in the field.Taking the bioassay test results as the standard,the rate of diagnostic dose method results reached 96.29%.（3）The highest specific activity of cytochrome P450 oxidase in ZC population is0.28（nmol/min/MG protein）.Compared with sensitive population,its specific activity is 7.00times,while the specific activity of CH,HZ and DWY are 3.50,3.00 and 1.50 times.The specific activity of glutathione-S-transferase in CH population is 38.09（μmol/min/MG protein）,which is 4.42 times higher than that of sensitive population,while the specific activity of ZC,HZ and DWY are 2.68,1.37 and 1.11 times higher than that of sensitive population respectively.HZ population has the highest esterase specific activity of9.08（μmol/min/MG protein）.Compared with sensitive population,its specific activity is 3.05times,while ZC,CH and DWY have the specific activity of 1.96,2.02 and 1.00 times that of sensitive population respectively.