PESTICIDE RESIDUES IN FOOD - 1981
Sponsored jointly by FAO and WHO
EVALUATIONS 1981
Food and Agriculture Organization of the United Nations
Rome
FAO PLANT PRODUCTION AND PROTECTION PAPER 42
pesticide residues in food:
1981 evaluations
the monographs
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, 23 November-2 December 1981
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
Rome 1982
DISULFOTON
Explanation
Disulfoton was evaluated by the JMPR in 1973, 1975 and 1979.* New
data on residues in alfalfa green forage were received from Bayer AG.
RESIDUES IN FOOD
RESIDUES RESULTING FROM SUPERVISED TRIALS
Alfalfa
Residue trials were carried out in 1975 and 1976 in a number
of states in the US. Applications were usually at 16 oz a.i./acre
(1.12 kg/ha) although 8 or 32 oz a.i./acre (0.56 or 2.24 kg/ha) were
used in two treatments. Formulations used were either 15 G granules or
a foliar spray based on a 6% liquid concentrate. Plot sizes varied,
and the volume applied was between 37 and 92 l/ha.
Rainfall was recorded for each trial and in the driest
conditions, the States of Arizona and California where the rainfall
was less than 3.8 cm, flood irrigation was applied.
Where there was adequate rainfall during the trial, most residues
were at or about the limit of determination, 0.01 mg/kg (not all
results at this level are recorded in Table 1) at 30 to 120 days after
treatment. The occasional high results can be related to rainfall or
irrigation. For example, the schedule resulting in the highest residue
of 4.26 mg/kg was as follows:
granular application 4 February
irrigation of 10 cm 27 February
sampling 28 February
Total rain during the period 4 February to 2 March was 1.8 cm.
Grass
Grass grown under pecan trees treated with 15% granules contained
up to 14 mg/kg, most results being in the range 0.5 to 10 mg/kg up to
60 days after treatment (Table 2).
* See Annex II for FAO and WHO documentation.
TABLE 1. Residues of disulfoton in alfalfa green forage
Interval last Application
application to Residues rate
sampling (days) (mg/kg) (kg a.i./ha)
granules 15 G broadcast
on established stubble
14 1.82, 1.31 1.12
4.26, 1.81 2.24
28 0.25, 0.25 1.12
0.86, 0.95 2.24
granules 15 G broadcast
on seedlings
45 0.1, 0.01 1.12
70 0.02, <0.01 1.12
89 0.2, <0.01 1.12
120 0.1, 0.1 1.12
foliar spray on
established stubble
30 0.16, 0.14, 0.01, 0.01
45 0.08, 0.03, 0.04, 0.01
60 0.02, <0.01, <0.01, <0.01
foliar spray on seedlings
46 11.3, 0.12, 1.0, 0.03, 0.02
65 12.0, 3.0, <0.01, <0.01
93 0.1, <0.01, <0.01
120 0.03, 0.25, 0.08, 0.03, 0.04
1 low rainfall + irrigation.
TABLE 2. Residues of disulfoton in grass
Interval last application Residues
to sampling (days) (mg/kg)
29/30 0.2, 2.2, 10.1
0.8, 3.2
45 0.8, 4.1, 13.9
0.6, 1.2
59/60 10, 4.0, 5.3
0.03, 0.7
73/75 1.5, 1.5
0.07, 0.3
87/90 0.5, 1.2, 3.1
0.03, 0.05
120/125 0.2, 0.1, 4.1
0.05, <0.01
EVALUATION
APPRAISAL
These data do not affect previous recommendations for levels to be expected in alfalfa hay.
REFERENCES
Chemagro Division of Mobay Chemical Corporation. Results of pesticides
1981 residue trials. (Unpublished)