CHLOROBENZILATE JMPR 1975
Explanation
At the 8th Session of the Codex Committee on Pesticide Residues
in 1975 a question was raised concerning the pre-harvest interval
considered by the Joint Meeting when establishing its recommendations
(Alinorm 76/24, para. 73). Chlorobenzilate was evaluated by the Joint
Meeting in 1965, 1968 and 1972.
Use pattern
Chlorobenzilate is applied as a wettable powder or emulsifiable
concentrate to apples and pears at rates ranging from 15 to 60 g/100 l
with 1 to 4 applications per season. Normally, treatment is required
in mid to late summer for the control of various mites, but depending
upon seasonal conditions and the effectiveness of biological control
agents it may be necessary to treat apple and pear crops within 7 to
14 days of harvest.
Residues found in supervised trials
In addition to the information reported in the 1965, 1968 and
1972 monographs further information has been published by Bartsch et
al. (1971). A summary of the data on residues in apples, pears and
walnuts is included in Table 1.
APPRAISAL
The data considered previously indicate that chlorobenzylate is
retained almost entirely in the surface layer of fruit. The residue is
stable to atmospheric and biological influences and, except an leaves
which are growing fairly rapidly the residue levels decline only
slowly with a half-life of more than 14 days.
The evidence available indicates that the previously recommended
maximum residue limit of 2 mg/kg for pears will cover the residues
resulting from current uses when there is a pre-harvest interval of
one week. However, in the case of apples it is likely that some
residues will exceed 2 mg/kg for four and possibly six weeks after
spraying.
The treatment of apples two weeks before harvest is not usually
required, but situations frequently occur where mite infestations will
require treatment two weeks before harvest. For this reason the Joint
Meeting in 1968 recommended a maximum residue limit of 5 mg/kg.
TABLE 1. Chlorobenzilate residues in various crops
Dosage and
formulationb Interval
(% or lb/100 US between last Residues
gal or/acre) and No. appl. and (ppm) and
Crop and Country (g.a.i./100 l of sampling Anal. plant parts
variety and year Ref.a or kg a.i./ha) Application dates appl. (days) methodc analysed
fruits
Apples USA G.A. 1 lb of 25 WP 12.VI. 1 0 UV 9.73
N. Jersey 30 g.a.i./100 l
(1952) 1 lb of 25 EC 12.VI. 1 0 UV 16.99
30 g.a.i./100 l
1 lb of 25 WP 18.VII./25.VII. 2 7 UV 4.81
30 g.a.i./100 l
2 lb of 25 WP 18.VII./25.VII. 2 7 UV 7.92
60 g.a.i./100 l
1 lb of 25 EC 18.VII./25.VII. 2 7 UV 3.40
30 g.a.i./100 l
Apples USA G.A. 1 lb of 25 WP 14.VIII. 1 33 UV 3.84 E. Bartsch
N. York 30 g.a.i./100 l 14.VIII. 1 33 UV 0.00 et al.
(1953) 1/2 lb of 25 WP 15.VI./30.VI./15.VII./ 5 56 UV 2.62
15 g.a.i./100 l 30.VII./12.VIII.
Apples USA G.A. 2 lb of 25 WP 29.VI./13.VII./1.VIII./ 4 0 GC 4.0
Red Oregon 60 g.a.i./100 l 16.VIII. 0 4.0
Delicious (1967) 6 5.3
6 2.8
13 4.8
13 3.2
30 1.9
30 2.1
42 1.8
42 1.9
TABLE 1. (Cont'd.)
Dosage and
formulationb Interval
(% or lb/100 US between last Residues
gal or/acre) and No. appl. and (ppm) and
Crop and Country (g.a.i./100 l of sampling Anal. plant parts
variety and year Ref.a or kg a.i./ha) Application dates appl. (days) methodc analysed
Pears USA G.A. 2 lb of 25 WP 21.VI./18.VII./19.VIII. 3 8 UV 0.53 Chlorobenzilate
Calif. 60 g.a.i./100 l 8 0.36 and
(1953) 8 0.51 chloropropylate
G.A. 2 lb of 25 WP 9.VI./4.VII. 2 60 UV 0.14
60 g.a.i./100 l 60 0.08
60 0.11
60 0.02
Pears USA G.A. 1-1/2 lb of 25 WP 26.V./19.VI. 2 31 UV 0.37 "
Bartlett Calif. 45 g.a.i./100 l 31 0.38
(1953) 31 0.42
shell meat
Walnuts USA G.A. 1) 0.76 lb a.i. of 1) 19.VII. 2 28 GC <0.1 <0.1 "
Hartley Calif. 4 E 0.85 kg
a.i./ha
(1966) 2) 2.25 lb a.i. of 2) 30.VIII. 28 <0.1 <0.1
4 E 2.5 kg
a.i./ha
+ surfactant before husk split
X-77 at 4 spray mixture:
oz./100 gal 200 gal/acre
G.A. 1) 1.5 lb a.i. of 1) 19.VII. 2 28 GC <0.1 <0.1
4 E 1.68 kg
a.i./ha
2) 4.5 lb a.i. of 2) 30.VII. 28 <0.1 <0.1
4 E 5.0 kg
a.i./ha
+ surfactant before husk split
X-77 at 4 oz/100 spray mixture:
gal 200 gal/acre
a References: G.A. = Geigy Chemical Corp., Ardsley (N.Y.): Residue reports, unpublished.
b Formulation: WP = wettable powder, EC = emulsifiable concentrate, and E = emulsifiable concentrate.
c Analytical method: UV = ultraviolet, and GC = gas chromatographic.
Apparently an error occurred in the preparation of the 1972
Monograph because the maximum residue limit for apples and pears,
carried forward from the previous monograph appears as "2 ppm" instead
of "5 ppm". The data published in the monographs of the 1968 Meeting
certainly support the need for a 5 mg/kg limit for apples whereas
2 mg/kg is sufficient for pears.
The new data demonstrate that when chlorobenzilate is applied to
apples according to the good agricultural practice approved in several
countries, the residues frequently exceed 2 mg/kg and can easily reach
5 mg/kg but in the case of pears the 2 mg/kg limit is not likely to be
exceeded. Accordingly the Meeting confirmed the 2 mg/kg limit for
pears and recommended that the maximum residue limit established for
apples in 1968 should be confirmed as 5 mg/kg.
RECOMMENDATION
The maximum residue limit for chlorobenzilate recommended in 1972
is corrected to the recommendation made in 1968 and the new data
considered by this Meeting as follows:
Pre-harvest interval
Maximum residue on which recommendations
Commodity limit are based (days)
Apples 5 mg/kg 14 days
REFERENCES
Bartsch, E., Eberle, D., Ramsteiner, K., Tomann, A. and Spindler, M.
(1971) The carbinole acarides: chlorobenzilate and chloropropylate. In
Gunther, F. A, and Gunther, J. D., Eds. "Residue reviews", 39:1.
See Also:
Toxicological Abbreviations
Chlorobenzilate (ICSC)
Chlorobenzilate (FAO Meeting Report PL/1965/10/1)
Chlorobenzilate (FAO/PL:1968/M/9/1)
Chlorobenzilate (WHO Pesticide Residues Series 2)
Chlorobenzilate (Pesticide residues in food: 1977 evaluations)
Chlorobenzilate (Pesticide residues in food: 1980 evaluations)
Chlorobenzilate (IARC Summary & Evaluation, Volume 5, 1974)
Chlorobenzilate (IARC Summary & Evaluation, Volume 30, 1983)