Residues and Persistence of Novel Insecticide HNPC-A3061 in Chinese Cabbages and Soils

Brochlorfenapyr, test code:HNPC-A3061; chemical name:1-(2-chloroethoxy)methyl-4-brom-2-(4-chlorophenyl)-5-tirfluoromethylpyrrol-3-nitrile), is a novel pyrrole insecticide discovered by Hunan Research Institute of Chemical Industry, and is used to control pest insects on crops such as vegetables, rice and cotton. Field experiments were conducted to study the residues and dissipation dynamics of HNPC-A3061 in Chinese cabbages, and soils in Hunan, Hebei and Jiangsu for two years. The initial deposition of HNPC-A3061 on Chinese cabbages was 2.686 mg·kg-1, 1.715 mg·kg-1and 2.603 mg·kg-1in 2012, and 4.859 mg·kg-1, 2.665 mg·kg-1and 1.755 mg·kg-1in 2013 for Hunan, Hebei and Jiangsu, respectively. The half life of HNPC-A3061 on Chinese cabbages was 5.28 d, 5.14 d and 6.16 d in 2012, and 7.17 d, 6.42 d and 10.73 d in 2013 for Hunan, Hebei and Jiangsu, respectively. The initial amounts of HNPC-A3061 deposited on soils were 1.284 mg·kg-1, 0.451 mg·kg-1and 0.298 mg·kg-1in 2012, and 0.705 mg·kg-1, 0.691 mg·kg-1and 0.648 mg·kg-1in 2013 for Hunan, Hebei and Jiangsu, respectively. In soils, HNPC-A3061 had a half life of 13.05 d, 7.87 d and 11.12 d in 2012, and 2.75 d, 2.32 d and 5.94 d in 2013 for Hunan, Hebei and Jiangsu, respectively. Based on the classification of pesticide residues of China, HNPC-A3061 was a low toxic and non-persistent pesticide. When spaying 3～4 times with the recommended dosages of 18 g a.i.·hm-2and 27 g a.i.·hm-2, the final maximum residue levels(MRL)of HNPC-A3061 in Chinese cabbages and soils were 0.290 mg·kg-1and 0.141 mg·kg-1at 14 d after the last application, respectively. These values were lower than the standard of 1.0 mg·kg-1with pre-harvest interval of 14 d established by US EPA for the same class insecticide chlorfenapyr in Chinese cabbages.