The degradation rates and residue levels of diazinon, pirimiphos‐methyl and chlorpyrifos in the leaves and fruits of pepper plants grown in commercial greenhouses were studied using g.l.c. Analysis of leaves at intervals following application showed that the initial residue of diazinon was higher than that of the other two insecticides, while its dissipation rate was faster. The dissipation of chlorpyrifos in fruits was faster than diazinon. The maximum residue levels (m.r.l.) of diazinon (0.5 mg kg−;1) and chlorpyrifos (0.1 mg kg−;1) were reached after 13 and 8 days of application respectively. With diazinon and pirimiphos‐methyl, sprayed 3 weeks before inflorescence, very low concentrations of both insecticides were found in fruits, although these compounds have no systemic behaviour. Chlorpyrifos residue level of 0‐2 mg kg −;1 in harvested fruits did not drop below m.r.l. after 11 days holding period.

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Phosphine gas (PH3) is a widely used fumigant for stored fruits and grains. Previous studies indicated that all residues of this gas are eliminated by normal aeration but the exact time has never been determined. The objective of this work was to determine the time required for desorption of phosphine from fumigated dates relative to aeration time and temperature. Flame photometric detection by gas chromatography was used for the detection of sorbed phosphine. Results indicate that the initial residue level of PH3 falls rapidly within 24 h after fumigation but residues persist for at least nine days. Higher residue levels were found in dates stored at low temperatures (4°C) than at 28°C. It is recommend that fumigated dates be marketed after longer periods of aeration, especially those aerated at temperatures of 4°C or less.