Diquat residues in lentil following preharvest treatment

Abstract

In a 2-yr study, residues of diquat were spectrophotometrically determined in lentil (Lens culinaris Medik.) seed and straw/chaff following preharvest treatment using 0.56 kg ha−1 at three crop growth stages. Diquat residues ranged from 12.9 to 17.3 mg kg−1 in the lentil straw/chaff one day after application and decreased to 1.1 to 6.0 mg kg−1 2 wk later. Diquat residues in the seed were in the order of 0.05 mg kg−1 or less regardless of time of sampling after spraying or growth stage of the crop at application. The limit of quantification of the analytical method was 0.04 mg kg−1, and recoveries of diquat from fortified seed and straw were in the order of 70%. Key words: Diquat, lentil, residues, spectrophotometric determination