Study On Safe Pesticides Combination Of Cowpea Based On Safety Interval-growth Stage Matching Strategy

Cowpea susceptible bean-pod borer and other pests,and its initial flowering Continuous picking the growth pattern of increased risk of pesticide residues,so that it is called the poison cowpea.Because of the characteristic of the continuous picking cowpea,cowpea registered medical security clearances are not more than 7 days,lead to registered pesticide varieties is less,cannot satisfy the production needed.For this study,we propose safety interval-growth stage matching strategy cowpea pest control research production process,the main contents are as follows:1.In zhejiang province was carried out by cowpea main pest occurrence and pesticide field research,results showed that the main insect pests for bean-pod bore,Thrips,aphids.There are 27 kinds of insecticides in common use,such as spinetoram and imidacloprid,only Chlorantraniliprole,spinetoram,cyhalothrin,cypermethrin for drug registration,on the basis of ten pesticides and metabolite safety condition is studied under this strategy.2.The best methods of UPLC-MS/MS and GC-MS/MS for the determination of ten pesticides and metabolite were established.The LOQ of the method were 0.01 mg/kg.And the average recoveries of this method ranged from 74% to 108%,and the RSD values ranged from 1.1% to 18%,all of which meet the requirements of pesticide residue test guidelines.3.Typical high-risk acephate and chlorpyrifos pesticide according to the different growth stages of pesticide residue and risk assessment of the results show that the acephate as alternative products of high toxic pesticide methamidophos,after using in cowpea increases the drug metabolism in the body and converted to disable pesticide methamidophos,toxicity,and safe intervals for up to 5 days.However,cowpea is picked every one or two days to podding stage,prone to excessive risk chlorpyrifos pesticide residual period is long,cowpea harvest time is short,the use of chlorpyrifos likely to cause excessive pesticide residues,and chlorpyrifos is highly toxic to aquatic organisms,and long-term use will do great harm to the environment,so our country banned acephate and the use of chlorpyrifos in cowpea production is very necessary.4.Has carried out more than spinetoram of seven kinds of alternative pesticides used in strategy under the framework of optimization,the results show that after cowpea use seven alternative agents from the peak of pod stage,spinetoram,imidacloprid,acetamiprid,emamectin benzoate,cyantraniliprole,lambda-cyhalothrin,chlorfenapyr below MRL values respectively at least 2 d,1 d,5 d,2 d,0 d,5 d,0 d.According to the result of the proposal on the premise of not more than dosage applied in field experiment,seven pesticides including spinetoram,imidacloprid,acetamiprid,emamectin benzoate,cyantraniliprole,lambdacyhalothrin,chlorfenapyr,et al.that all can be used in sowing period and seedling stage.Acetamiprid can be used once at the initial time of flowering,and the safety interval was 5d.Lambda-cyhalothrin and chlorfenapyr can be used twice at the initial time of flowering,and the safety interval were 5 d.Spinetoram,imidacloprid,emamectin benzoate and cyantraniliprole degrade quickly and can be used at the peak of pod stage.The following conclusions were drawn from the above results:1.The main insect pests and applicable pesticides in cowpea were identified by investigating the occurrence of main insect pests and drug use in cowpea in Zhejiang Province.2.The established residue analysis methods of ten pesticides and metabolite in the test samples were accurate and precise in line with the requirements of pesticide residue test guidelines,and can be used for the detection of a large number of different samples.3.Based on the field experiment of the application of typical high risk pesticides acephate and chlorpyrifos in cowpea during different growth periods,the results of residual and dietary intake risk assessment were analyzed.It was verified that it was necessary to ban the use of acephate and chlorpyrifos in cowpea production in China.4.Through field trials and dietary intake risk assessment of seven alternative pesticides such as spinetoram,the effectiveness of the safe interval-growth stage matching strategy was verified,and recommendations for the whole use of pesticides in cowpea were obtained based on this strategy.