RESIDUE AND ANALYTICAL ASPECTS
Methamidophos is a systemic organophosphorus insecticide and also a metabolite of acephate. It was first evaluated in 1976. The 1994 JMPR recommended withdrawal of the CXL for melons except watermelon and the draft MRLs for broccoli, head cabbages, cauliflower, citrus fruits, egg plant, peach and tomato which had been held at Step 7B by the 1992 CCPR (ALINORM 93/24, paras 119-123). The manufacturer indicated that information on GAP and data on residues would be available to support new MRLs for these commodities.
The Meeting received data on supervised trials, and information on GAP, the stability of residues in stored analytical samples, methods of residue analysis, and the fate of residues during food processing. The supervised trials included applications of methamidophos to broccoli, head cabbages, cauliflowers, egg plants, melons, peaches and tomatoes; and of acephate to broccoli, Brussels sprouts, head cabbages, cauliflowers, citrus fruits and tomatoes. The Meeting estimated the residues of methamidophos arising from the use of each compound.
Since methamidophos has been listed by the CCPR as a candidate for periodic review but not yet scheduled, and in view of the difficulties encountered by the present Meeting in evaluating the available data without the original studies, the Meeting recommended that the CCPR should schedule methamidophos for periodic review.
