Document Type : Original Article


Plant Protection Dept., Fac. Agric., Zagazig Univ., Egypt.


Field experiment was conducted to determine residues of pyridalyl insecticide on tomato leaves and fruits. Tomato plants were sprayed with the insecticide pyridalyl (Pleo 50% EC) at the rate of 100 ml/fad. on January, 2014. QuEChERS (catchers) method was used for extraction and clean-up of the samples. Residues were determined 2 hours, 1, 2, 3, 5, 7, 10 and 14 days post-treatment using UHPLC-UV. The recovery percentages were 89.29 and 96.73 % for leaves and fruits, respectively. The results revealed that the residue concentrations of pyridalyl on leaves and fruits, two hours after single application of the insecticide were 1.007 and 0.815 mg a.i./kg, respectively. The insecticide residues on fruits were 0.707, 0.569 and 0.474 mg a.i./kg after 1, 2 and 3 days and reached 0.2 mg a.i./kg after 14 days. The corresponding residues on leaves were 0.808, 0.646, 0.637 and 0.284 mg a.i./kg after 1, 2, 3 and 14 days. The rates of degradation (k values) were 0.100 and 0.115 on leaves and fruits, respectively. The corresponding half-life times (t 0.5) were 6.950 and 6.050 days on leaves and fruits, respectively. The residues on tomato fruits were below the maximum residual level (MRL) value reported by the European Food Safety Authority (EFSA, 2013).  Thus, tomato fruits could be safely harvested for human consumption and for processing purposes.