Bioactivity Of Broflanilide On Main Rice Pests And Its Residue In Rice Field

Broflanilide?3-benzamido-N-?4-7 fluorine-2-methyl isopropyl aniline?phenyl?benzamido)is a meta-diamide novel insecticide developed by Mitsui Agricultural Chemical Company of Japan and BASF.Based on the experiment of broflanilide on the biological activities of rice stem borer,rice leaf roller and rice planthopper,and on the growth and decline of natural enemy spiders in rice field,the constant and residue analysis method of broflanilide were devoloped.The degradation dynamics and final residues of broflanilide in rice and environment were determined.The results are as follows:?1?Broflanilide on Chilo suppressalis and Cnaphalocrocis medinalis had better bioactivity.The results in the greenhouse indicated that the LD50 of broflanilide on Chilo suppressalis and Cnaphalocrocis medinalis were 0.0107?g/g and 0.0104?g/g,respectively.Its bioactivities were 1.51 times and 1.62 times as high as those of flubendiamide,respectively.The indoor activity of broflanilide on rice planthopper was low,and its mortality was lower than 10%at 1 mg/L of the highest dosage in 48 h after treatment.The results of field trials showed that the efficacies of broflanilide 5%SC at26.25 and 30.00 g/hm² on Chilo suppressalis and Cnaphalocrocis medinalis were both superior to or significantly better than those of broflanilide 5%SC at 18.75 and 22.50g/hm² and that of the control agent flubendiamide 20%WDG at 25.50 g/hm².The population densities of rice planthopper?Nilaparvata lugens and Sogatella furcifera?treated with broflanilide 5%SC at 18.75,22.50,26.25 and 30.00 g/hm² had no significant difference compared with the control agent flubendiamide 20%WDG at 25.50 g/hm² and blank control treatment.The spider densities of different treatments restored to the blank control level in 14 days after spray.?2?The methods for determination of broflanilide constant and residue were established by reversed-phase high performance liquid chromatography?HPLC?.The chromatographic conditions were systematically investigated by HPLC with C₁₈8 column as fix phase,the mixture solution of acetonitrile and water?75:25,by vol?as the mobile phase and UV detector at 254nm wavelength in constant analysis.The result showed that the linear correlation coefficients for broflanilide was 0.9999.The standard deviation was0.054 with the variation coefficient of 1.06%.And the average recovery rate was 101.22%.The limit of detection for broflanilide of this method was 10^-10 g in the residue analysis.The limit of quantification?LOQ?was 0.0005 mg/kg in paddy water,0.0025 mg/kg in soil and rice,and 0.005 mg/kg in plant and rice husk.The average recoveries of broflanilide ranged from 88.95%to 96.81%with the relative standard deviations?RSD?of 4.12-7.44while fortifiled concentrations of broflanilide in paddy water were 0.01-0.5 mg/kg.The average recovery ranged from 85.21%to 100.17%with RSD of 2.09%⁹.23%while fortifiled concentrations of broflanilide in soil,rice plant,rice husk and rice were 0.01-0.5mg/kg.?3?The residual dynamic experiment in the paddy field showed that the half-lives of broflanilide were in the range of 0.46-2.46 days in paddy water,2.09-5.34 days in paddy soil,and 1.31-3.32 days in rice plant while broflanilide at 1.5 times of the recommended dosage was applied.The results of the final residue test showed that no broflanilide was detected in rice,and residual levels of broflanilide were lower than 0.05 mg/kg in soil,rice plants and rice husks while broflanilide at recommended dosage and 1.5 times of the recommended dosage were applied two times and three times,respectively.