Persistence of Oxadiargyl 80 per cent WP in/on Onion

Results of a supervised field experiment conducted during Rabi cropping season (October-March) 2014–15 to study the dissipation pattern of oxadiargyl in/on onion and soil by single application at recommended (160 g a.i. ha⁻¹) and the double the recommended dose (320 g a.i. ha⁻¹) at 3 d after onion transplanting, are reported. The samples of immature onion with leaves were monitored periodically at 0, 3, 5, 7, 10, 15 and 20 d till the residues reached below quantification limit (BQL). Mature onion and soil samples were collected at harvest. The initial residues of oxadiargyl in immature onion leaves were 4.88 (at recommended) and 6.48 mg kg⁻¹ (double the recommended). These dissipated to BQL on 25^th d at both the doses. No residue was detected in mature onion and soil. The half lives (T_1/2) in immature onion leaves were 3.09 and 3.55 d at the recommended and double the recommended doses respectively.