PESTICIDE RESIDUES IN FOOD - 1983
Sponsored jointly by FAO and WHO
EVALUATIONS 1983
Data and recommendations of the joint meeting
of the FAO Panel of Experts on Pesticide Residues
in Food and the Environment and the
WHO Expert Group on Pesticide Residues
Geneva, 5 - 14 December 1983
Food and Agriculture Organization of the United Nations
Rome 1985
DIFLUBENZURON
RESIDUES
Explanation
Diflubenzuron was first evaluated in 1981.1 The attention of
the Meeting was drawn to the fact that the data supporting the 1981
estimates for maximum residue levels (MRLs) in Brussels sprouts,
cabbage and plums had been inadvertently omitted from the 1981
evaluations. This addendum corrects that error.
RESIDUES IN FOOD AND THEIR EVALUATION
RESIDUES RESULTING FROM SUPERVISED TRIALS
Two supervised trials on Brussels sprouts in 1976 in the
Netherlands resulted in residues of up to approximately 0.3 mg/kg in
harvested crops 58 days after treatment (see Table 1, Philips-Duphar
1978a). Trials on cabbage in the Netherlands in 1974 and the Federal
Republic of Germany in 1975 showed that initial residues in Savoy
cabbage of up to 0.7 mg/kg declined to 0.1 mg/kg or less in 28 days.
Similarly, in oxheart cabbage, initial residues of up to 3 mg/kg
declined to about 0.1 mg/kg or less in 28 days (see Table 1,
Philips-Duphar 1976).
In Brussels sprouts, the analytical method gave a mean recovery
of 88 percent over a range of diflubenzuron from 0.02 mg/kg to 2
mg/kg. Mean recoveries for Savoy cabbage were 92 percent and for
oxheart cabbage 85 percent, both over a range of 0.03 mg/kg to 2
mg/kg. The limit of determination was from 0.02 mg/kg for Brussels
sprouts to 0.05 mg/kg for cabbage.
A single trial on Victoria plums in 1977 in the Netherlands
showed a residue of less than 0.1 mg/kg 27 days after treatment. Mean
recoveries with the analytical method were 98 percent over a range of
0.01 mg/kg (the limit of determination) to 2 mg/kg of diflubenzuron
(see Table 1, Philips-Duphar 1977).
1 See Annex 2 for FAO and WHO documentation.
Table 1 Diflubenzuron residues in Brussels sprouts, cabbage and plums
Interval from application Residue
Crop Treatment to sampling (days) (mg/kg)
Brussels sprouts 0.001% 15 0.07
(Netherlands) conc'n spray 58 <0.02
1976 0.01% 16 0.33
conc'n spray 58 0.31
Brussels sprouts 250 g a.i./ha 7 0.94
(UK) 14 0.81
19781 21 0.6
28 0.68
Savoy cabbage 25 g a.i. in 0 0.7, 0.24, 0.39, 0.23
(Netherlands) 2 500 l water/
1974 ha 7 0.13, 0.22, 0.22, 0.08,
14 0.21, 0.17, 0.10, 0.05
28 0.03,<0.03, <0.03, <0.03
0 0.22, 0.45, 0.14,<0.03
7 0.08, 0.20, 0.10, 0.07
14 0.06, 0.09, 0.10, 0.03
28 0.06, 0.11, 0.08, 0.06
Oxheart 100 g a.i. in 0 1.8, 2.9, 2.0, 2.9
Cabbage 1 000 l 7 0.9, 0.6, 1.2, 0.9
(Germany) water/ha 14 0.4, 0.3, 0.5, 0.4
1975 28 0.07, 0.06, 0.1, 0.1
Plums 0.02% 27 0.02
(Netherlands ) conc'n
1976 0.04% 27 0.06
conc'n
1 Source: Philips-Duphar 1978b.
APPRAISAL
The Meeting reviewed the data on residues in mushrooms in the
1981 evaluations and concluded that an estimated MRL of 0.1 mg/kg was
more appropriate than the figure of 0.2 mg/kg previously estimated. It
was recognized, however, that at the highest rate of application
studied there was a possibility the 0.1 mg/kg might be marginally
exceeded at the first cropping. The Meeting noted that the data
supporting the 1981 estimates for MRLs in Brussels sprouts, cabbage
and plums had been accidentally omitted from the 1981 evaluations. On
reviewing these data, the Meeting concluded that they would not
support the MRL for plums estimated in 1981 and recommended that it be
withdrawn until further data become available.
REFERENCES- RESIDUES
Philips-Duphar Report on residues of diflubenzuron in cabbage,
1976 Netherlands 1974, Germany 1975. (Unpublished)
Philips-Duphar Report on residues of diflubenzuron in plums,
1977 Netherlands 1976. (Unpublished)
Philips-Duphar Report on residues of diflubenzuron in Brussels
1978a sprouts, Netherlands 1976. (Unpublished)
Philips-Duphar Report on residues of diflubenzuron in Brussels
1978b sprouts, UK 1978. (Unpublished)