Persistence and Degradation Behaviour of Dimethoate in Grapes

Abstract

Through a field experiment, the dissipation pattern of dimethoate in grapes was evaluated during December 2020 - February 2021. Dimethoate 30%EC was sprayed twice at ten-days interval at recommended (X) dose (445 g a.i ha-1) and double the recommended (2x) dose (890 g a.i ha-1). The samples were collected from 0 (2hr), 1, 3, 5, 7, 10, 15 and 20 days or till degradation to below detectable level (BDL) and at harvest time. The residues were extracted by the modified QuEChERS method and analyzed by LCMS. The method performance was satisfactory in terms of SANTE guidelines and with good linearity (r2>0.99). The mean total dimethoate residue including omethoate was 1.047 and 2.168 mg kg-1 at x and 2x doses, respectively with half-lives of 5.47 and 5.59 days. The calculated Risk Quotient (RQ) at both x and 2x dose with Good Agricultural Practices (GAP) indicated that for dimethoate these are not safe for human health due to the intake of residue.