METHOMYL JMPR 1977
Methomyl was reviewed by the 1975 and 1976 Joint Meetings (FAO/WHO
1976, 1977b) and no toxicological data were made available. On the
other hand, fairly extensive data on use patterns and residues were
supplied. As a result of this imbalance, the 1976 Joint Meeting was
unable to determine an acceptable daily intake but it suggested
guideline levels for residues in several crops. Full toxicological
data were required and an improved residue analysis procedure,
information on the fate of the compound during storage or in
processing and information on national use patterns and residue data
from countries other than Australia, Netherlands, and USA were listed
None of the requirements have been met, except that additional data
were submitted by the Netherlands on the use pattern in tomatoes and
bell peppers and residues in tomatoes.
RESIDUES IN FOOD AND THEIR EVALUATION
In the Netherlands, methomyl is used in tomatoes and bell peppers at
the dosage rate of 25 g/100 1. at 1700 1/ha, with a recommended
pre-harvest interval of 3 days. Both 25% and 20% EC formulations are
RESIDUES RESULTING FROM SUPERVISED TRIALS
The residues obtained in the Netherlands on tomatoes were generally
low, 0.01-0.06 mg/kg at the pre-harvest interval of 0-3 days and
application rates of 0.75-1.25 kg a.i./ha.
METHODS OF RESIDUE ANALYSIS
Although the method of Pease and Kirkland (1968) suffers from emulsion
and interference problems, it may be used for regulatory purposes on a
case-to-case basis. Some refinements or modifications are still
required for it to be accepted as a regulatory method. In the
Netherlands, a modification of the procedure was used and no
difficulties were encountered. The limit of determination was 0.01
The only submission received by the 1977 Joint Meeting was that from
the Netherlands which dealt with use patterns in tomatoes and bell
peppers and residue data on tomatoes. Residues of methomyl were
generally low, 0.01-0.06 mg/kg, at the pre-harvest interval of 0-3
days. The residue method used was a modification of that of Pease and
Kirkland (1968) and no difficulties were encountered. The limit of
determination was 0.01 mg/kg.
FURTHER WORK OR INFORMATION
As listed in the Report of the 1976 Joint Meeting (FAO/WHO 1977a, P.
Pease, H.L. and Kirkland, J.J. (1968) Determination of methomyl
residues using micro colorimetric gas chromatography. J. Agr. Food
Chem., 16: 554-557.
FAO/WHO (1976) 1975 evaluations of some pesticide residues in food.
AGP:1975/M/13; WHO Pesticide Residues Series No. 5.
FAO/WHO (1977a) Pesticide residues in food. Plant Production and
Protection Series No. 8, WHO Technical Report Series No. 612.
FAO/WHO 1976 evaluations of some pesticide residues in food.