PESTICIDE RESIDUES IN FOOD - 1979
Sponsored jointly by FAO and WHO
EVALUATIONS 1979
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, 3-12 December 1979
DIAZINON
Explanation
Diazinon has been evaluated on a number of previous occasions. An
ADI of 0.002 mg/kg has been established and MRLs have been
recommended for diazinon in a wide range of food commodities.
The New Zealand Ministry of Agriculture requested the meeting to
consider diazinon residues in kiwi fruit with a view to
recommending a maximum residue limit.
RESIDUES IN FOOD AND THEIR EVALUATION
USE PATTERN
Diazinon is used, in combination with carbaryl, as an alternative
to phosmet. Four sprayings would normally be applied,
mid-December, January, February and March using 1.125 kg/ha at each
application with a maximum of 4.5 kg/ha in any one season. With
kiwi fruit being picked in May, the time between the last
application and picking is at least 30 days. The major pest
against which diazinon is used is greedy scale (Hemiberlesia
rapax).
Studies published by Love and Ferguson (1977) indicate that
diazinon residues may be determined by gas chromatography on kiwi
fruit with a recovery of 100-110% at 0.3-1.7 mg/kg. Their results
include figures for rates of diminution of residue levels between
final spraying and harvest.
Table 1 summarized the results from a monitoring program conducted
by the New Zealand Ministry of Agriculture and Fisheries between
1973 and 1978. Of the 90 samples examined, the highest residue
detected was 0.29 mg/kg.
In a trial carried out in 1973, three applications of diazinon 50%
wettable powder were made at monthly intervals, at 3 rates, to a
trial plantation of kiwi fruit. Residues of diazinon were
determined and are expressed on a whole fruit basis in Table 2.
These data explain why the New Zealand authorities chose to
restrict the spray program to a maximum of 4.5 kg/ha for the season
and to enforce a time interval between the last spray and harvest
of 30 days.
Table 1. Diazinon Residues on Kiwi fruit -
Results from Grower Use
Year Range No.
1973 <0.01 15
0.01-0.05 11
0.05-0.1 5
>0.1 1
32
1974 <0.01 13
0.01-0.05 32
0.05-0.1 3
>0.1* 0
48
1978 <0.01 4
0.01-0.05 4
0.05-0.1 1
>0.1* 1
10
* Highest residue 0.29 mg/kg
Table 2. Diazinon Residues in Kiwi fruit
Application rate
(kg a.i./ha per Replicate Prespray
application) day - 1
1 2 5 8 11 15 21 28 35
2.9 1 0.09 1.3 1.3 1.2 0.61 0.48 0.51 0.24 0.27 -
2.0 2 0.09 1.5 0.8 0.8 0.91 0.56 0.46 0.35 0.35 -
4.3 1 0.09 3.0 1.9 1.3 0.92 0.74 0.38 0.38 0.29 0.12
4.3 2 0.13 2.4 1.5 1.2 0.54 0.61 0.62 0.28 0.23 0.16
5.7 1 0.16 4.6 2.7 1.9 1.3 1.2 0.66 0.36 0.40 0.21
5.7 2 0.11 1.2 1.9 1.3 0.53 0.41 0.43 0.24 0.27 0.19
APPRAISAL
Diazinon is used along with other insecticides for the control of
greedy scale on kiwi fruit in New Zealand.
The residue data from supervised trials and from monitoring the use of
diazinon by growers give a clear picture of the level and fate of
diazinon residues on kiwi fruit. These data reveal that over 90% of
the residue is retained in inedible skin, there being no significant
residue in the edible pulp. The residue consists of the parent
compound alone.
RECOMMENDATION
The following maximum residue limit for diazinon are recommended:
Commodity Limit (mg/kg) Preharvest interval on which
recommendations are based
Kiwi fruit 0.5 30 days
REFERENCES
New Zealand. Submission from the New Zealand Ministry of Agriculture
and Fisheries, Wellington, New Zealand to FAO, 22 September 1978.
Love, J.L. and Ferguson, A.M. - Pesticide residues and Greedy Scale
control on Kiwi fruit. New Zealand journal of Agricultural Research
20: 95-103.