Preparation And Field Application Evaluation Of Imidacloprid·hexaflumuron 30% SC

Bradysia odoriphaga is the one of the major insect pests on Chinese chives which seriously affects its quality and yield.With the quick developmet of the national agricultural industrialization,the area of Chinese chives keep increasing,thus contributing to a more and more serious condition considering its damage on Chinese chives.In recent years,the prevention of this pest was mainly depended on the organophosphorus or neonicotinoid insecticides.Because of the single varieties of insecticides and unsuitable application methods,low efficacy was reported in many areas even they adopted the high dosage of pesticidesIt’s urgent to explore a scientific method to deal with the terrible problem.Imidacloprid has favorable efficacy in controlling B.odoriphaga,besides,it also shows low toxicity to mammals,cheap and can be re-excavated.Among the insect growth regulators,hexaflumuron can affect the insects for a long time and has a low toxicity to the environment.Considering the advantages of the above two kinds of pesticides,we can mix them to control B.odoriphaga.Then,the adsorption and leaching of the two insecticide in the soil was investigated.To what extent did the dispersing agents influence their leaching abilities were also researched.After obtained a suspension concentrate with low leaching,we had evaluated the distribution of imidacloprid and hexaflumuron in the soil under spraying and flooding-irrigation conditions.The mobility of active ingredients in the field and the control efficacies of tank mixiture(mix the two active ingredients)and suspension concentrate(contains two active ingredients)in managing B.odoriphaga were also investigated.Main results were displayed as follows.1.The adsorption and leaching of thiamethoxam in three different soils(Sandy soil,Silt loam soil,Shajiang black soil)were investigated by using oscillation equilibrium experiments,soil thin layer chromatography and column leaching methods to study the influence of physical and chemical properties of the soil on the adsorption and leaching behavior of imidacloprid and hexaflumuron.The results showed that the content of clay is one of the most important factors that affect the adsorption of imidacloprid and hexaflumuron in the soil,followed by the content of organic matter.The leaching ability of the three kinds of soil ranked as sandy soil> silt loam> shajiang black soil.However,imidacloprid has a potential risk of groundwater contamination compared with hexaflumuron.2.The ananalytical method of imidacloprid and hexaflumuron in the soil and water was established by HPLC.The results showed that the recoveries of imidacloprid and hexaflumuron in the soil were 85.31%-91.85% and 84.17-93.66% respectively.The coefficient of variation was 1.50%-2.53% and1.73%-2.17% respectively.The recoveries of imidacloprid and hexaflumuron in water were 84.17%-93.66% and 86.62%-94.38%,respectively.The coefficient of variation was 1.60%-2.02%,and 0.96%-1.80% respectively.The experimental results are in accordance with the requirements of pesticide residue analysis.3.The influences of dispersing agents on the leaching of imidacloprid and hexaflumuron were also investigated in the current study.The leaching ability of imidacloprid and hexaflumuron in the YUS-WG4 sample was the lowest as well as that of Ning-ru 34#.Imidacloprid and hexaflumuron in the sample 6 both had the lowest leaching among different formulations,which met the quality control indexes of the suspension concentrate.The favorable formula consists of 15% imidacloprid,15% hexaflumuron,1% Ning-ru 34#,1.5% YUS-WG4,1.6% magnesium silicate,0.12% xanthan gum,2% ethylene glycol,0.4% SAG630 and 63.38% water.4.The distribution of imidacloprid and hexaflumuron in the soil under spraying and flooding-irrigation conditions was investigated.The mobility of active ingredients in the field and the control efficacies of tank mixiture(mix the two active ingredients)and suspension concentrate(contains two active ingredients)in managing B.odoriphaga were also investigated.The results showed that pesticides in spraying treatment was more concentrated than that in flooding-irrigation and they were also easier to reach the target sites.Imidacloprid and hexaflumuron were mainly maintained in the 0-10 cm and 0-5 cm depth in the soil.In the treatment of irrigation,the concentration was lower with the distance from the headwater.The pesticide concentrations in the soil of spraying treatment was significantly higher than that of flooding-irrigation.The leaching of active ingredients for tank mixiture(mix the two active ingredients)was higher than that for suspension concentrate(contains two active ingredients).The number of B.odoriphaga in tank mixiture treatment was also slightly higher.Both of the two treatments can maintained favorable control efficacies in managing B.odoriphaga for 120 days.