PHOSALONE JMPR 1976
Explanation
Phosalone was evaluated at the Joint Meeting in 1972 and, on
the basis of data then available, a maximum residue limit of 2
mg/kg for phosalone on cherries was recommended (FAO/WHO 1973). The
Canadian Delegation to the Codex Committee on Pesticide Residues in
1975 advised that this limit was not sufficient to cover the
residues resulting from approved uses of phosalone on cherries in
Canada and the U.S.A., and that additional data would be supplied.
Results of trials in Canada and the U.S.A. submitted by Canada
were evaluated by the Meeting and the following monograph addendum
is provided.
RESIDUES IN FOOD AND THEIR EVALUATION
USE PATTERN
In Canada, foliage applications of wettable powders or
emulsifiable solutions are used at rates of 1 - 1.5 kg a.i./ ha or
300-400 g a.i./100 1 to within 7 days of harvest for the control of
a number of insects, including aphids, mites and cherry fruit
flies. In the U.S.A. rates are somewhat higher.
RESIDUES RESULTING FROM SUPERVISED TRIALS
Results of 15 supervised trials in various regions of the
U.S.A. and Canada were submitted to the Meeting. Random samples
were collected at various intervals from 0 to 70 days after the
last of several applications. Most treatments were made at the
officially approved rate but for comparison several trials were
conducted at rates up to 2.5 times normal.
All samples were frozen before shipment to the laboratory
where a spectro-photometric method (limit of determination 0.1
mg/kg) or a gas-chromatographic method (limit of determination 0.02
mg/kg) was used for analysis. Recovery studies showed an average
recovery of 92%.
The results are summarised in Table 1. The residue level
shortly after application is usually about 10 mg/kg. Its rate of
decline is slow except during the period of intensive growth of
fruit when apparently there is significant dilution. Generally the
residue levels at harvest range above 5 mg/kg when treatment has
been made 7-8 days prior to the normal harvest date. Though the
trials included both sweet and sour cherries the data do not
provide an adequate basis for determining whether there is any
significant difference in the residue pattern for the two
varieties. On the basis of these data the Meeting concluded that
the maximum residue limit for phosalone on cherries should be
raised to 10 mg/kg.
TABLE 1. Phosalone residues in cherries, U.S.A.
Application, Residues, mg/kg, at interval (days) after application
no. X rate,
g a.i./100 l
Variety Year and formulation 0 1 3 7 14 21 30
Bing 1967 3 X 500 EC 7.70 5.0 3.3 2.8 1.7
1968 3 X 380 EC 9.71 6.15 5.25
3 X 500 EC 14.56 9.72 9.32
(1.3X)
1969 1 X 500 WP 0.5
1969 3 X 500 EC 5.7 3.1 3.2 0.28
(2x)
1973 5 X 600 EC 10.03 3.82 8.5 6.5
1973 4 X 750 EC 6.4 5.2 4.0 5.1
Hedelfinger 1969 4 X 450 WP 2.9 1.2
4 X 600 WP 3.1 2.1
Montmorency* 1969 4 X 450 WP 5.3 2.9
4 X 600 WP 6.9 5.0
1968 3 X 500 EC 9.6 6.3 5.9
1970 3 X 750 EC 20.1 9.0 4.5 1.1
(2.5x)
TABLE 1. (Cont'd.)
Application, Residues, mg/kg, at interval (days) after application
no. X rate,
g a.i./100 l
Variety Year and formulation 0 1 3 7 14 21 30
Royal Ann 1967 3 X 750 EC 10.2 6.1 5.92 4.1
1968 3 X 500 EC 6.75 5.57 4.48 1.98
(2x)
Sour 1964 4 X 750 EC 10.67 5.95 4.05 0.80
Sweet 1964 4 X 500 EC 10.32 10.68 11.1 8.25 1.96 0.12
1973 5 X 1000 WP 10.24 7.35 3.65
* This trial in Canada, not U.S.A.
A trial involving the application of phosalone at 10 times the
normal rate was conducted to determine whether a significant amount of
the oxygen analogue could be formed. Samples drawn over the period 29
to 8 days prior to harvest were examined by thin layer chromatography.
It was estimated that even at the excessively high rate the amount of
phosalone oxygen analogue present was less than 0.1 mg/kg.
RECOMMENDATIONS
The maximum residue limit for phosalone on cherries is amended as
follows. The limit is for phosalone parent compound.
Commodity Limit, mg/kg
Cherries 10
REFERENCES
FAO/WHO 1972 Evaluation of some pesticide residues in food.
1973 AGP:1972/M/9/1; WHO Pesticide Residue series No.
2.