Residue and Dissipation Study of Oxadiargyl in Spinach

A field experiment was conducted in an alfisol to study the degradation of oxadiargyl and its residues in edible parts of spinach at College Farm, College of Agriculture, Rajendranagar during rabi and kharif seasons of 2007–08. The rate of dissipation of oxadiargyl showed first order kinetics. Oxadiargyl dissipated with half varying from 16.72 to 20 d when applied at the rate of 0.75 and 1.5 kg a.i ha⁻¹ under FYM applied and without FYM conditions. Residues of oxadiargyl in field soil were analysed by using gas chromatograph and there has been 100 per cent dissipation of oxadiargyl was observed at the time of harvest of crop. The observed half life values were lower for lower dose of applied herbicide as compared to higher dose and the field half life of oxadiargyl was more under without FYM applied conditions as compared to with FYM. Very low levels of residues were detected in spinach leaves and there were below the maximum residue limit of 0.05 mg kg⁻¹. The residues were absent at harvest. Based on the present results, pre-emergence application of oxadiargyl in spinach for weed management could be considered safe from the point of consumption of green leaves as the residues were below Maximum residue limits.