Residues of Fluvalinate and Permethrin on Flue-cured Tobacco

High-performance liquid chromatography (HPLC) with C₁₈ reverse-phase columns was used to determine residues of fluvalinate and permethrin applied in the field to flue-cured tobacco in 1980 and 1981. Methods were developed to determine residue levels in both green and cured samples. In 1980 field tests, residues of fluvalinate applied at rates of 0.1 and 0.2 kg/ha averaged 3.3 and 7.2 ppm, respectively, on green tobacco harvested immediately after application, and declined to 0.3 and 2.7 ppm by 12 days after application. In 1981, with the same application rates, residues averaged 1.7 and 3.0 ppm (0 time) and declined to 0.4 and 0.5 ppm after 16 days, respectively. A new formulation of fluvalinate, applied at 0.06 and 0.01 kg/ha, averaged 0.9 and 1.3 ppm on day 0 and declined to 0.3 and 0.6 ppm after 16 days, respectively. Flue curing reduced fluvalinate residues approximately by 61 % both years. Immediately after application, residues of permethrin, applied at 0.2 kg/ha, averaged 9.6 ppm in 1980 and at application rates of 0.1 and 0.2 kg/ha averaged 3.5 and 3.8 ppm, respectively, in 1981. Residues declined to 7.0 ppm after 12 days in 1980 and to 3.2 and 3.5 ppm after 16 days in 1981. Losses of permethrin due to curing averaged 67 %.