CHLOROTHALONIL JMPR 1978
Explanation
Chlorothalonil was reviewed by the Joint Meeting in 1974 and
1977 (FAO/WHO, 1975b, 1978b). During the tenth session of the Codex
Committee on Pesticide Residues, data were promised that would
allow MRLs for new commodities to be recommended (Alinorm 79/24,
para 153). The data received are evaluated in this monograph
addendum.
RESIDUES IN FOOD AND THEIR EVALUATION
USE PATTERN
Data were available on residues in some cereals, in grapes and
in strawberries. There was insufficient information on the
registered uses in grapes and strawberries to establish MRLs or the
basis of good agricultural practice, Although information on
registered use for cereals was also scarce, it was considered that
an MRL could be proposed on the basis of an interval of 6 weeks
between last application and use, Residues data are based on the
use of a 75% wettable powder, a 720 g/l liquid and a wettable
powder containing 20% chlorothalonil, 22% zineb and 40% sulphur.
RESIDUES RESULTING FROM SUPERVISED TRIALS
The data on residues of chlorothalonil in some types of
cereals are summarized in Table 1 (de Mey, 1977).
National MRLs reported to the Meeting
In addition to the national MRLs reviewed by the 1974 JMPR,
the following were reported.
Country Commodity MRL (mg/kg)
Japan cereals 0.5
Netherlands cereals 0.2
Switzerland cereals 0.3
APPRAISAL
On the basis of the residue data on winter wheat, summer wheat
and winter barley, it appears that after use of chlorothalonil at
1 to 3 kg ai/ha and taking into account a period of 6 weeks between
the last application and harvest, a temporary maximum residue limit
of 0.2 can be recommended.
TABLE 1. Chlorothalonil in cereals
Residues (mg/kg) at interval (days) after application
Crop Year Rate kg ai/ha Formulation
(Country) 1/(application
unless indicated) 24 28 30 36 42 43 45 47 52 56 61
Winter wheat 1975 1.2 wp 20% 0.02
Winter wheat 1975 1.2 wp 20% <0.01
(Belgium)
Winter wheat 1974 1.5 wp 75% 0.16
Winter wheat 1974 1.5 wp 75% 0.01
Winter wheat 1974 1.5 wp 75% <0.01
Winter wheat 1975 1.5 wp 75% <0.01 <0.01
Winter wheat 1975 n.i.1/ liquid <0.01 <0.01
Winter wheat 1975 1.62 liquid 0.068
720 g/l
Winter wheat 1976 1.08 liquid 0.021
720 g/l
Winter wheat 1976 1.08 liquid 0.088
(Germany) 720 g/l
TABLE 1. (Cont'd)
Residues (mg/kg) at interval (days) after application
Crop Year Rate kg ai/ha Formulation
(Country) 1/(application
unless indicated) 24 28 30 36 42 43 45 47 52 56 61
Winter wheat 1974 1.2 wp 20% 0.52
(ears & grain)
Winter wheat 1974 +1.2 wp 20% 0.46
(ears & grain)
(Netherlands)
Wheat 1970 1.08 flowable 0.01
Wheat 1970 1.08 flowable 0.0175
Wheat 1970 1.08 n.i.1/ 0.01
Wheat 1970 1.08 n.i.1/ 0.01
Wheat 1976 1.08 n.i.1/ 0.0105
Wheat 1976 1.08 n.i.1/ 0.0155
(France)
Wheat 1975 2.51 wp 75% <0.01
Wheat 1975 2.51 wp 75% <0.01
(U.K.)
TABLE 1. (Cont'd)
Residues (mg/kg) at interval (days) after application
Crop Year Rate kg ai/ha Formulation
(Country) 1/ (application
unless indicated) 21 31 35 39 40 41 47 48 49 61
Summer wheat 1974 1.125 wp 20% <0.01
Summer wheat 1975 1.62 liquid
720 g/l 0.29
Summer wheat 1975 1.62 liquid
720 g/l 0.03
Summer wheat 1976 1.08 liquid
720 g/l 0.04
Summer wheat 1976 1.08 liquid
720 g/l 0.097
Summer wheat 1976 1.08 liquid
720 g/l 0.04
Summer wheat 1976 1.06 liquid
720 g/l 0.777
(Germany)
Winter barley 1976 1.7 liquid
720 g/l <0.01
Winter barley 1976 1.7 liquid
720 g/l 0.09
TABLE 1. (Cont'd)
Residues (mg/kg) at interval (days) after application
Crop Year Rate kg ai/ha Formulation
(Country) 1/(application
unless indicated) 21 31 35 39 40 41 47 48 49 61
Winter barley 1976 1.7 liquid
720 g/l <0.01
Winter barley 1976 1.7 liquid
720 g/l 0.10
Winter barley 1976 1.7 liquid
720 g/l <0.01
Winter barley 1976 1.7 liquid
720 g/l 0.07
(Belgium)
Winter barley 1975 1.5 wp 75% <0.01
100 days
Winter barley 1975 1.5 + 1.5 wp 75% <0.01
(Tunisia) 80 days
1/ not indicated
RECOMMENDATIONS
In addition to former recommendations the following temporary MRL
is proposed:
Commodity Temporary MRL Pre-harvest interval
Cereals 0.2 6 weeks
REFERENCES
de Mey, W. Residue Analysis of Chlorothalonil in cereals, Vol. I
(1977) and II.
FAO/WHO Pesticide Residues in Food 1974.
(1975b)
FAO/WHO Pesticide Residues in Food 1977.
(1978)
See Also:
Toxicological Abbreviations