Fate of Malathion in Some Vegetable Crops in Saudi Arabia PDF

Keywords

vegetables, Saudi Arabia, malathion

Abstract

Malathion is being widely used for pest control on vegetable crops in Saudi Arabia. Studies were initiated to determine the levels of malathion residues on lettuce, cucumber and tomato plants at different intervals after the application of malathion. Foliage and/or fruit samples from treated and untreated plants were extracted for the residue analysis by gas- liquid chromatography. The initial amounts of malathion residue and their subsequent decrease after spray varied among the three vegetable crops. Moreover, the level of residues in lettuce was higher in the greenhouse than in the field. The half-life values of malathion were about1 or 2 days for the tested vegetables. The residues of malathion in cucumber and tomatoes even at 0 hr after spray were well below the 'established tolerance levels', while that of lettuce was 23 ppm. However, the residue level of malathion in lettuce subsided well below the critical limit at 5 days after application.