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)