PESTICIDE RESIDUES IN FOOD - 1983
Sponsored jointly by FAO and WHO
EVALUATIONS 1983
Data and recommendations of the 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, 5 - 14 December 1983
Food and Agriculture Organization of the United Nations
Rome 1985
PERMETHRIN
RESIDUES
Explanation
Permethrin was evaluated at the 1979, 1980, 1981 and 1982
Meetings.1 Data now available for review include additional
information on residues in Phaseolus beans and data which facilitate a
first review of permethrin residues on peanuts and on sorghum fodder.
RESIDUES IN FOOD AND THEIR EVALUATION
RESIDUES RESULTING FROM SUPERVISED TRIALS
Snap beans
Permethrin is effective at rates of 0.11-0.22 kg a.i./ha against
Spodoptera spp. and Heliothis spp. on beans. A preharvest withholding
interval of three to seven days can generally be observed. On the
basis of initial data available from trials in The Netherlands, United
Kingdom and United States, the 1979 Meeting recommended an MRL of 0.5
mg/kg for whole green beans.
Additional data are now available from 11 trials which were
conducted in the United States during 1979-81. In all cases permethrin
was applied at 0.11 kg a.i./ha, by either ground or aerial means.
Samples taken during the two weeks following the last of 4-10
applications were analysed by gas chromatography with an electron
capture detector (GC-EC), the method which was reviewed at the 1979
Meeting. Results are shown in Table 1. During the first week after the
last application, permethrin residue levels declined slowly and were
in a range up to 0.61 mg/kg; two of 11 trials gave values at or above
the existing MRL of 0.5 mg/kg. Residues after ground application were
appreciably higher than after aerial applications (Pearson 1983).
Sorghum
In preharvest applications, permethrin was effective against
sorghum midge, Contarinia sorghicola, at rates of 0.055-0.11 kg
a.i./ha, and against fall armyworm, Laphygma frugiperda and chinch
bugs, Blissus spp., at rates of 0.11-0.22 kg a.i./ha. A preharvest
interval of 14 days was valid in sorghum grown for forage or of 28
days in that grown for grain.
__________
1 See Annex 2 for FAO and WHO documentation.
Residue data on grain sorghum were available from six trials,
which were conducted in the United States in 1980-81, in which
permethrin was applied by ground equipment at 0.22 kg a.i./ha. All but
one of the samples of grain taken 27-31 days after application and
analysed by GC-EC were shown to contain permethrin residues of
0.16-0.79 mg/kg, i.e. within the MRL of 2 mg/kg proposed by the 1980
Meeting for postharvest uses of permethrin on cereal grains. One value
of 4 mg/kg was recorded (Table 2) (Fitzpatrick & Pearson 1983).
Samples of forage taken 14-15 days after application and analysed
by GC-EC were shown to contain residues of 0.95-5.6 mg/kg, all values
being corrected to 28.9 percent dry matter content (Table 2). When
corrected to a dry weight basis, these figures were, with one
exception, above or close to the corresponding levels found in stover
left when grain was harvested 27 to 31 days after application. The
exception, of 24 mg/kg in stover, coincided with the case in which
grain residues were also high (see preceding paragraph) (Table 2)
(Fitzpatrick & Pearson 1983).
Peanuts
Permethrin proved effective against velvetbean caterpillar,
Anticarsia gemmatilis, and potato leafhopper, Empoasca fabae, at rates
of 0.055-O.11 kg a.i./ha and against fall armyworm, Laphygma
frugiperda, cutworms, Agrotis spp., rednecked peanutworm, Stegasta
bosqueella and Heliothis spp., at rates of 0.11-0.22 kg a.i./ha. A
preharvest interval of 14 days can usually be observed. Residue data
on peanuts were available from five trials conducted in the United
States during 1979-1980, in which permethrin was applied by ground
equipment at 0.22 kg a.i./ha. Samples of peanuts taken 12-15 days
after application and analysed by GC-EC contained permethrin levels of
0.02-0.1 mg/kg (Table 3). Corresponding levels in the foliage were
3-11 mg/kg (Fitzpatrick 1982).
APPRAISAL
Additional data on residues enabled the Meeting to estimate
maximum residue levels for sorghum fodder and peanuts. It was
considered that the level for peanuts should apply to the group of
legume oilseeds. New residues data on phaseolus beans indicated that
the existing MRL of 0.5 mg/kg could be exceeded in good agricultural
practice and the Meeting estimated an increased maximum level of
1 mg/kg. The commodity description should be changed from beans (whole
green) to beans (with pod). All three estimates were considered
suitable for establishing MRLs.
Table 1. Permethrin Residues in Snap Beans Following Supervised Trials - United States
Trial Location Rate of Spray Volume Number of Method of Interval Between Permethrin
And Year Application (l/ha) Applications Application Last Application Residue (mg/kg)2
(kg ai/ha)1 And Sampling (corrected for
(Days) % recovery)
Florida 0.11 900 5 Ground 0 0.61
1979 1 0.49
3 0.60
7 0.61
0.11 900 10 Ground 0 0.32
1 0.39
3 0.28
7 0.45
Florida 0.11 45 7 Aerial 3 0.06
1980
South Carolina 0.11 450 4 Ground 3 0.27
1981
Delaware 0.11 45 4 Aerial 3 Trace
1980
New York State 0.11 350 4 Ground 0 0.12
1979 1 0.24
3 0.26
7 0.21
0.11 45 4 Aerial 0 0.09
1 0.09
3 0.09
Table 1 (continued)
Trial Location Rate of Spray Volume Number of Method of Interval Between Permethrin
And Year Application (l/ha) Applications Application Last Application Residue (mg/kg)2
(kg ai/ha)1 And Sampling (corrected for
(Days) % recovery)
Minnesota 0.11 450 4 Ground 3 0.10
1980
45 4 Aerial 3 0.04
Wisconsin 0.11 950 5 Ground 3 0.22
1980
Oregon 0.11 330 4 Ground 0 0.50
1979 1 0.47
3 0.54
7 0.12
14 0.07
1 A 24% E.C. formulation was used.
2 Limit of determination : 0.01 mg/kg.
Table 2 Permethrin Residues in Sorghum Grain and Fodder - United States
Trial Location Rate of Spray Volume Number of Interval Between Permethrin Residue (mg/kg)2
and Year Application1 (1/ha) Applications Last Application (corrected for % recovery)
(kg ai/ha) And Sampling
(Days) Grain Stover3 Fodder4
Georgia 0.22 135 2 29 0.76 4.1 -
1980
Georgia 0.22 540 2 14 - - 4.8
1980 28 - 9.2 -
Florida 0.22 330 2 14 - - 0.95
1981 27 0.16 - -
Texas 0.22 280 2 15 - - 2.3
1981 29 0.71 3.7 -
Maryland 0.22 360 2 14 - - 2.4
1981 31 0.79 7.8 -
Missouri 0.22 190 2 15 - - 5.6
1981 30 4.0 24 -
Missouri 0.22 190 2 15 - - 2.2
1981 30 0.62 8.8 -
1 A 24% E.C. formulation was used.
2 Limit of determination : 0.02 mg/kg,
3 Stover values were corrected to 90.2% dry matter,
4 Forage values were corrected to 28.9% dry matter.
Table 3 Permethrin Residues in Peanuts - United States
Trial Location Rate of Spray Volume Number of Interval Between Permethrin
And Year Application1 (1/ha) Applications Last Application Residue (mg/kg)2
(kg ai/ha) And Sampling (corrected for
(Days) % recovery)
North Carolina 0.22 135 4 14 Trace
1979
Georgia 0.22 120 4 14 0.04
1979
Alabama 0.22 45 4 14 0.10
1979
Texas 0.22 325 5 12 0.04
1980
Florida 0.22 180-450 4 15 0.02
1980
1 A 24% E.C. formulation was used.
2 Limit of determination : 0.01 mg/kg.
RECOMMENDATIONS
The recommendations refer to permethrin (sum of isomers).
Metabolites are not included.
Commodity MRL Remarks
(mg/kg)
beans (with pod) 1 increased from 0.5 mg/kg for
"beans, whole green"
sorghum fodder 20 on a dry weight basis
legume oilseeds 0.1
REFERENCES - RESIDUES
Fitzpatrick, R.D. Permethrin and permethrin metabolite residues on
1982 peanuts and peanuts process fractions. ICI Americas Inc.,
Agricultural Chemicals Division Report No. TMU0894/B.
(Unpublished)
Fitzpatrick, R.D. & Pearson, F.J. Permethrin residues on grain
1983 sorghum. ICI Americas Inc., Agricultural Chemicals Division
Report No. TMU0847/B (Revised) (Unpublished)
Pearson, F.J. Permethrin and permethrin metabolite residues on
1983 snapbeans. ICI Americas Inc., Agricultural Chemicals
Division Report No. TMU0971/B. (Unpublished)
See Also:
Toxicological Abbreviations
Permethrin (EHC 94, 1990)
Permethrin (HSG 33, 1989)
Permethrin (ICSC)
PERMETHRIN (JECFA Evaluation)
Permethrin (Pesticide residues in food: 1979 evaluations)
Permethrin (Pesticide residues in food: 1980 evaluations)
Permethrin (Pesticide residues in food: 1981 evaluations)
Permethrin (Pesticide residues in food: 1982 evaluations)
Permethrin (Pesticide residues in food: 1984 evaluations)
Permethrin (Pesticide residues in food: 1987 evaluations Part II Toxicology)
Permethrin (JMPR Evaluations 1999 Part II Toxicological)
Permethrin (UKPID)
Permethrin (IARC Summary & Evaluation, Volume 53, 1991)