Dissipation pattern of spiromesifen in/on brinjal fruits

Abstract

A supervised field trial was conducted to study the dissipation of spiromesifen at Naraseepuram village, Thondamuthur, Coimbatore, on the brinjal variety CO 2, during January – February, 2018. The samples were collected up to 15 days after pesticide application along with control and processed by modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method. The final estimation of residues was carried out on Ultra High Performance Liquid Chromatography (UHPLC) with diode array detector. The mean initial deposit after two spraying of spiromesifen in/on brinjal fruit @ 96 g a.i ha-1 and 192 g a.i ha-1 were 0.715 μg g-1 and 1.123 μg g-1, respectively. More than 80 percent of spiromesifen residues got dissipated on 3 days after treatment. The residues persisted up to 5 days after treatment and further dissipated to Below Detectable Limit (BDL < 0.05 μg g-1) on 7 days after treatment. Dissipation of spiromesifen followed first order reaction kinetics and the calculated half life was 1.32 and 2.18 days, respectively for 96 g a.i ha-1 and 192 g a.i ha-1 dose. The safe waiting period of 1.40 and 2.18 days is recommended for brinjal sprayed with spiromesifen @ 96 g a.i ha-1 and 192 g a.i ha-1 dose respectively.