Dissipation, persistence and risk assessment of imidacloprid 17.8 SL on tomato

Abstract

Studies were conducted to evaluate the persistence, dissipation, and risk assessment of Imidacloprid 17.8 SL in tomato. After the third spray, fruit samples were separately collected from treated and untreated control plots at various intervals. The tomato samples were processed following modified QuEChERS technique and analyzed through UHPLC. When tomato was treated at 35and 70 g a.i. ha-1after the third spray, the average initial deposits of imidacloprid on tomato were reported to be 0.34 and 0.65 mg kg-1, respectively. After five and seven days following the last application at the single dose and double dose, imidacloprid residue in tomato was dissipated at below the LOQ of 0.05 mg kg-1. For risk assessment of imidacloprid on tomato, the TMRC were calculated and compared with MPI. The results showed that, the TMRC values were below MPI in all the sampling days for both the dosages. Marketable size fruits should be plucked before the application of any insecticide so that 2-3 days will required for next picking. Hence, the study suggested aminimum waiting period of three days for safe consumption of tomato when applied with imidacloprid at a single dose.