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Eight pesticide residues in tomato samples collected in the area of Souss Massa Valley (Southern Morocco) were analyzed. The detected residue levels ranged from 0.001 to 0.400 mg kg for dicofol, from 0.003 to 0.170 mg kg for procymidone, from 0.001 to 0.250 mg kg for chlorothalonil, from 0.050 to 0.500 mg kg for bifenthrin, from 0.001 to 0.010 mg kg for λ-cyhalothrin, from 0.001 to 0.300 mg kg for cypermethrin, from 0.010 to 1 mg kg for deltamethrin and from 0.003 to 1.123 mg kg for endosulfan. European MRL for endosulfan in tomatoes set in 0.500 mg kg, was exceeded in 8 samples, and MRL for deltamethrin set in 0.300 mg kg for tomatoes was exceeded in 2 samples. [ABSTRACT FROM AUTHOR]

A study was undertaken to evaluate the rate of decline of the residues of dicofol and difenoconazole in a Daniela tomato variety grown in an experimental plastic greenhouse. These two pesticides were selected on the basis of previous excesses of 22 and 25%, respectively, found in tomato samples cultivated in 2005 in eastern Morocco. Each group of tomatoes was subjected to a single chemical treatment when close to ripeness; pesticides were applied at the doses recommended by the manufacturers. Fruit samples were periodically collected until the end of the preharvest interval (p.i.). Residue levels of dicofol and difenoconazole were determined by liquid-liquid extraction (LLE), solid phase extraction (SPE) and gas chromatography with electron capture detection (GC-ECD). Residue levels of dicofol ranged from 1.54 to 0.26 mg/kg and the levels of difenoconazole ranged from 2.00 to 0.28 mg/kg, with median values of 0.82 and 0.99 mg/kg, respectively. The residual concentrations after the p.i. were below the legal limits. The difenoconazole value was high in the tomato plants of group VI, which were also treated with copper sulfate. This result indicates that extreme care must be taken when spraying doses of this fungicide, particularly on tomato varieties that are to be used fresh. [ABSTRACT FROM AUTHOR]

Dissipation of bifenthrin and λ-cyhalothrin pyrethroid insecticides, under environmental conditions, was evaluated on green beans grown in experimental greenhouses (Souss Massa valley, Morocco). Pesticide residues were determined by gas chromatography with micro electron-capture detector (GC-μECD) after dichloromethane extraction and cleanup on florisil phase cartridges. In the case of field experiments, a random block scheme was employed. Each block contained 25 plants in a single row and tests were carried out in triplicates applying pesticides at the recommended doses by the manufacturers. Fruit samples were periodically taken until the end of the preharvest interval (p.i.). The results obtained showed that the p.i of bifenthrin in green bean were 4 days in the winter and 3.5 days in the spring, whereas that for λ-cyhalothrin 8 days was found in the winter and 7.5 days in the spring. Consequently, it is possible to consider the European Union maximum residue limit (EU MRL) values compatible with the proper agricultural practices used for growing green bean in the plastic greenhouse of Souss Massa valley in South Morocco. Bifenthrin had a degradation of first-order kinetics, whereas that of levels for λ-cyhalothrin residue can not be interpreted by the use of a first order model.