| Abstract: | Five agricultural crops were treated with OO-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate (chlorpyrifos) granular or emulsifiable concentrate formulations at dosages from 0.5 to 6.0 kg (a.i.)/ha and at different periods before harvest. Chlorpyrifos residues were determined by gas chromatography after extraction and sweep co-distillation clean-up. Low residue levels were found. The average values in lettuce were 0.046 and 0.070 part/million, in sugar beet leaves 0.037 to 0.128 part/million and roots <0.005 to 0.038 part/million; no chlorpyrifos was detected in carrots, potatoes and cured tobacco leaves at the limit of the method (0.005 part/million). |
