Residue analysis of butocarboxim and aldicarb applied in a drip-irrigated peach grove by the HPLC post-column fluorogenic labeling technique

Abstract

The new high-performance liquid chromatography (HPLC) post-column fluorogenic labeling technique was used for the analysis of residues of butocarboxim, aldicarb and their sulfoxide and sulfone metabolites in peach leaves and fruits. In order to simplify the procedure, the different metabolites were separated by column chromatography during the cleanup process and the residues were determined by HPLC employing an aqueous methanol solvent in the isocratic mode. The limit of detection for the two insecticides was 0.1 μg/g in the leaves and 0.02 μg/g in the fruit. Aldicarb (10% granular formulation) and butocarboxim (50% E.C. diluted 1:5 with water) were applied to the soil in a drip-irrigated peach grove, by placement under one dripper on one side of each tree. The insecticides were taken up by the tree and distributed almost equally on both sides of the tree. The concentration of the insecticides was somewhat lower in the younger leaves. Residue levels of 0.4 to 0.9 μg/g were detected in the fruits at harvest, 10 and 18 days after the last treatment. Based on the results from the field experiment it was concluded that one of the advantages of drip irrigation was that it enabled adequate control of the green leafhopper (Asymmetrasca decedens) throughout the summer with relatively low dosages of systemic insecticides.