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    PESTICIDE RESIDUES IN FOOD - 1984


    Sponsored jointly by FAO and WHO






    EVALUATIONS 1984




    The monographs



    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
    Rome, 24 September - 3 October 1984

    Food and Agriculture Organization of the United Nations
    Rome 1985

    CYHALOTHRIN

    RESIDUES IN FOOD AND THEIR EVALUATION

    USE PATTERN

         Cyhalothrin is a pyrethroid insecticide with a high level of
    activity against a wide range of Lepidoptera, Hemiptera, Diptera and
    Coleoptera spp. It also has miticidal activity. The compound is a
    stomach, contact and residual insecticide. It shows adulticidal,
    ovicidal and, particularly, larvicidal activity. It is also extremely
    effective against a great number of insects resistant to standard
    treatments such as organochlorines and organophosphates.

         Like other photostable synthetic pyrethroids, cyhalothrin is
    relatively stable to degradation in sunlight. This allows it to be
    used as a practical tool in agriculture. Cyhalothrin is not plant
    systemic and has very little fumigant or translaminar activity.

         The miticidal activity of cyhalothrin is seen as being
    particularly useful as an adjunct to the control of other insects,
    which the compound provides in tree fruits such as apples. When used
    for lepidopterous pest control, it greatly reduces the risk of mite
    build-up that is experienced with some other insecticides in top fruit
    and can reduce, or even eliminate, the need for mite sprays.

         Owing in part to its short persistence in soil and in part to a
    lack of systemic effect, cyhalothrin is of only limited value when
    used as a soil insecticide. It can, however, give useful control of
    cutworms when applied as a crop/ground spray. Cyhalothrin has no
    molluscicidal or nematicidal activity.

         Preventive treatments are generally more effective than curative
    treatments against major pests, such as boring caterpillars or leaf
    miners. A programme of sprays is usually required, particularly during
    more active growth stages of the plant and when the potential for 
    re-infestation remains high. Best results are obtained using good
    spray cover, particularly when cyhalothrin is used during the early
    development stages of the pest.

    RESIDUES RESULTING FROM SUPERVISED TRIALS

         Cyhalothrin residues have been determined in a range of crops
    taken from supervised trials in several different countries.

         Samples from trials conducted outside the United Kingdom were
    frozen and transported by air freight to laboratories in the United
    Kingdom, where they were stored in a deep freeze (-20░C) until
    required for analysis. Fresh samples from trials in the United Kingdom
    were frozen upon receipt. Cyhalothrin residues in crops stored deep
    frozen have been shown to be stable for a 12-month period (Swaine &
    Sapiets, 1984).

         Cyhalothrin residues were determined by gas chromatography using
    an electron-capture detector, as described under "Methods of Residue
    Analysis".

    Pome Fruits

         At rates of 20-40 mg/kg a.i. in the spray, or 40-80 g a.i./ha,
    cyhalothrin gives excellent control of a complex of insects on apples,
    including winter moth (Operophtera brumata), tortrix moths
    (Archips podana and Adoxophyes orana), codling moth (Cydia
    pomonella) , apple sucker (Psylla mali) and apple sawfly
    (Hoplocampa testudinea) .  A programme of at least three sprays per
    season is normally required, with an interval of at least two weeks
    between the last application and first harvest. As an acaricide,
    50-100 mg/kg a.i. in the spray, or at least 100 g a.i./ha, is needed
    for economic control of fruit tree red spider mite (Panonychus ulmi)
    and of Tetranychidae.

         During 1982-83, supervised residue trials on apples or pears were
    conducted in Cyprus, Japan, South Africa, Spain and the United
    Kingdom, using either 5 percent W.P. or 10 percent E.C. formulations.
    At rates needed for lepidopterous insect control, the maximum residue
    level in apples immediately after application did not exceed
    0.5 mg/kg. As in the cases of permethrin and cypermethrin (FAO/WHO,
    1980) 1/, cyhalothrin levels on apples decline relatively slowly.
    Nevertheless, at rates needed for lepidopterous insect control,
    cyhalothrin levels were consistently below 0.2 mg/kg two weeks after
    the last application (Table 1) (Swaine et al., 1983a,b,c,d).

         Results of a trial on pears in Cyprus were also consistent with
    these findings (Swaine et al., 1983e).

         In a comparative trial in South Africa, cyhalothrin residue
    levels on apples and pears were similar after various intervals in the
    32 days following the application of a 10 percent E.C. formulation at
    40 or 80 mg/kg a.i. in the spray, applied to "run-off" (Table 2)
    (Swaine et al., 1983b; 1984).

    Cabbage and Chinese Cabbage

         At rates of approximately 10-20 g a.i./ha, cyhalothrin gives good
    control of a range of insects on cabbage, including Spodoptera spp.,
    cabbage loopers (Trichoplusia ni), cabbage moths and butterflies
    (Plutella and Pieris spp.), aphids (Myzus and Brevicoryne
    brassicae) and whitefly (Trialeurodes vaporarium). A programme of
    sprays may be required, depending on the location, pest spectrum and
    infestation pressure. An interval of two to four days between last
    spraying and harvest is often possible; in some situations it may be
    possible to observe an interval as long as seven days.

              

    1/  See Annex 2 for FAO and WHO documentation

         During 1982-83, trials were conducted in Spain, the United
    Kingdom and the United States, using either a 5 percent W.P. or
    10 percent E.C. formulation. Cyhalothrin was applied at two different
    rates at each site and there was good correlation within each trial
    between the initial residue found after the last application and the
    rate of application. There was greater variation in initial residues
    between sites. The data indicated over all that cyhalothrin has a
    relatively shorter initial half-life, of two to five days, on cabbages
    than on apples. This is consistent with the earlier findings with
    permethrin and cypermethrin (FAO/WHO 1980). Levels on cabbage were
    generally below 0.2 mg/kg within a few days of spraying (Table 3)
    (Sapiets, 1984a,b; Swaine et al., 1983f). There was no obvious
    build-up in cyhalothrin residue levels on cabbage after repeated
    applications (Sapiets, 1984b).

    Other Crops

         Cyhalothrin residues data are also available on Swiss chard,
    peaches, grapes, maize, sorghum and tea (Sapiets, 1984c).

    FATE OF RESIDUES

    In Plants

         14C-cyclopropyl-labelled cyhalothrin, containing approximately
    10 percent of the 14C-cyclopropyl-labelled 1RS-cis-E form of
    the molecule, was formulated as a 10 percent emulsifiable concentrate
    formulation, diluted with water and spotted onto young growing apple
    fruits. A polythene shelter erected over the tree protected the fruits
    from direct rainfall but allowed transmission of the ultraviolet
    radiation present in sunlight. The surfaces of the apples chosen for
    treatment were those exposed directly to the predominant direction of
    incident sunlight. After 56 days, at least 89 percent of the
    radioactivity recovered from treated peel was due to unchanged
    pyrethroid. The remainder of the radioactivity extracted with aqueous
    acetone was polar; acid hydrolysis produced an organosoluble fraction,
    which contained almost entirely 1RS-cis-3-(Z-2-chloro-3,3,3-
    trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylic acid,
    although the presence of about 14 percent of this radioactivity
    in the 1RS-trans form was evidence of a certain amount of
    photoisomerization. The applied radioactivity was not translocated
    away from the treated area of peel. The flesh from below the treated
    area of fruit harvested at 28 and 56 days after treatment contained
    less than 1 percent of the recovered radioactivity (Hall & Leahey,
    1979).

         14C-cyclopropyl-labelled cyhalothrin, prepared as an aqueous
    dilution of a 10 percent E.C. formulation, was spotted at a rate
    equivalent to approximately 25 g a.i./ha onto the leaves of cabbage
    plants grown in pots. The plants were exposed to sunlight but were
    protected from rainfall and covered overnight with a polythene cover.


        TABLE 1.  Cyhalothrin Residues in Apples from Supervised Trials

                                                                                                                                              

    Country/       Formulation       Rate           Volume        No.      Interval last                      Residues (mg/kg)
    year                          (g a.i./ha)       of spray               spray to                                                           
                                                    (l/ha)                 sampling (days)     R157836            Rl19321           Total
                                                                                                                                              

    Japan 1        5% W.P.        25 mg/kg a.i.     6 300         3              7             0.09, 0.10         0.06, 0.07        0.15, 0.17
    1982                          in spray                                      14             0.05, 0.05         0.03, 0.04        0.08, 0.09
                                  (0.0025%)                                     21             0.02,<0.006        0.01,<0.004       0.03,<0.01

                                                    3 000         3              7             0.09, 0.09         0.07, 0.07        0.16, 0.16
                                                                                14             0.08, 0.08         0.06, 0.06        0.14, 0.14
                                                                                21             0.09, 0.06         0.06, 0.04        0.15, 0.10

    Spain          10% E.C.       25 mg/kg a.i.     Sprayed       4              0             0.06               0.04              0.10
    1982                          in spray          to "run-                     1             0.05               0.04              0.09
                                  (0.0025%)         off"                         3             0.04               0.03              0.07
                                                                                 7             0.03               0.02              0.05

                                  50 mg/kg a.i.     Sprayed       4              0             0.07               0.06              0.13
                                  in spray          to "run-                     1             0.07               0.05              0.12
                                  (0.005%)          off"                         3             0.07               0.06              0.13
                                                                                 7             0.04               0.03              0.07

    South          10% E.C.       40 mg/kg a.i.     Sprayed       1              0             0.06               0.05              0.11
    Africa                        in spray          to "run-                     1             0.08               0.06              0.14
    1982-83                       (0.007%)          off"                         2             0.06               0.05              0.11
                                  (80 g/ha)                                      4             0.07               0.05              0.12
                                                                                 8             0.07               0.06              0.13
                                                                                16             0.06               0.05              0.11
                                                                                32             0.02               0.02              0.04
                                                                                                                                              

    TABLE 1.  (continued)

                                                                                                                                              

    Country/       Formulation       Rate           Volume        No.      Interval last                      Residues (mg/kg)
    year                          (g a.i./ha)       of spray               spray to                                                           
                                                    (l/ha)                 sampling (days)     R157836            Rl19321           Total
                                                                                                                                              

                                  80 mg/kg a.i.     Sprayed       1              0             0.21               0.16              0.37
                                  (.0.008%)         to "run-                     1             0.24               0.19              0.43
                                  (160 g/ha)        off"                         2             0.24               0.18              0.42
                                                                                 4             0.18               0.13              0.31
                                                                                 8             0.14               0.10              0.24
                                                                                16             0.11               0.08              0.19
                                                                                32             0.12               0.09              0.21

    United         10% E.C.       45 g a.i./ha      560           1              0             0.03               0.02              0.05
    Kingdom 2                                                                    7             0.02               0.01              0.03
    1982                                                                        14             <0.006             <0.004            <0.01

                                  45 g a.i./ha      560           1              0             0.04               0.03              0.07
                                                                                 7             0.02               0.02              0.04
                                                                                14             0.01               <0.004            <0.014

                                  1x18 g a.i./ha    560           3             14             0.04               0.02              0.06
                                  and
                                  2x45 g a.i./ha

                                  1x24 g a.i./ha    560           2             40             0.01               0.01              0.02
                                  and
                                  1x60 g a.i./ha

                                  25 mg/kg a.i.     Sprayed       2              0             0.05, 0.12         0.04, 0.09        0.09, 0.21
                                  in spray          to "run-                     1             0.06, 0.11         0.05, 0.08        0.11, 0.19
                                  (50 g/ha)         off"                       3-4             0.04, 0.12         0.03, 0.09        0.07, 0.21
                                                                                 7             0.04, 0.08         0.04, 0.06        0.08, 0.14

                                                                                                                                              

    TABLE 1.  (continued)

                                                                                                                                              

    Country/       Formulation       Rate           Volume        No.      Interval last                      Residues (mg/kg)
    year                          (g a.i./ha)       of spray               spray to                                                           
                                                    (l/ha)                 sampling (days)     R157836            Rl19321           Total
                                                                                                                                              

                                  50 mg/kg a.i.     Sprayed       2              0             0.12, 0.11         0.10, 0.09        0.22, 0.20
                                  in spray          to "run-                     1             0.12, 0.16         0.09, 0.13        0.21, 0.28
                                  (100 g/ha)        off"                       3-4             0.08, 0.17         0.06, 0.12        0.14, 0.29
                                                                                 7             0.07, 0 12         0.06, 0.09        0.13. 0.21
                                                                                                                                              

    1  The duplicate results are on replicate samples from the same trial
    2  The duplicate results are on single samples from two different trials in different locationsť

    TABLE 2.  Cyhalothrin Residues in Apples and Pears from Supervised Trials, South Africa1

                                                                                                   
                       Application
                                                    Interval spray            Total residues
    Rate                Volume         No.          to sampling                  (mg/kg)
    (mg/kg a.i.)        of spray                    (days)                Apples         Pears
                                                                                                   

    40                  Sprayed to     1                  0               0.11           0.12
                        "run-off"                         1               0.14           0 17
    (80 g/ha)                                             2               0.11           0.16
                                                          4               0.12           0.16
                                                          8               0.13           0.16
                                                         16               0.11           0.14
                                                         32               0.04           0.07

    80                  Sprayed to     1                  0               0.37           0.29
                        "run-off"                         1               0.43           0.29
    (160 g/ha)                                            2               0.42           0.32
                                                          4               0.31           0.25
                                                          8               0.24           0.21
                                                         16               0.19           0.17
                                                         32               0.21           0.14
                                                                                                   

    1  All trials done in 1982 using 10 percent E.C. formulation

    TABLE 3.  Cyhalothrin Residues in Cabbage from Supervised Trials

                                                                                                                                         
                                                                                                    Residues (mg/kg)
    Country/                     Rate         Volume     No.    Interval last                                                            
    year           Formulation   (g a.i./ha)  of spray          spray to            R157836             Rl19321             Total
                   used                       (1/ha)            sampling (days)                                             Cyhalothrin
                                                                                                                                         

    Spain          10% E.C.      20           300        4           0              0.44                0.31                0.75
    1983                                                             3              0.25                0.18                0.43
    (on                                                              7              0.18                0.13                0.32
    Chinese
    cabbage)                     40           300        4           0              0.58                0.43                1.0
                                                                     3              0.28                0.21                0.49
                                                                     7              0.28                0.20                0.48

    United 1       5% W.P.       75           3 000      2          14              -                   -                   0.06, 0.08
    Kingdom                                              3           0              -                   -                   0.36, 0.34
    1983                                                             3              0.01, 0.04          0.01, 0.03          0.02, 0.07
                                                                     7              0.01, 0.01          0.01, 0.004         0.02, 0.01
                                                                    14              <0.006,<0.006       <0.004,<0.004       <0.01,<0.01

    United         10% E.C.      10           225        6           0              0.07                0.04                0.11
    States                                                           1              0.06                0.03                0.09
    1982                                                             3              0.02                0.01                0.03
                                                                     7              0.01                0.01                0.02

                                 20           225        6           0              0.20                0.13                0.33
                                                                     1              0.05                0.04                0.09
                                                                     3              0.05                0.02                0.07
                                                                     7              0.04                0.03                0.07
                                                                                                                                         

    1  The duplicate results are on single samples from two different varieties on the same site sprayed at the same time.
    
    After six weeks, 54 percent of the radioactivity was still present as
    the intact pyrethroid. Some photoisomerization was indicated by the
    interconversion of cis and trans isomers and of Z and E
    isomers, although even after six weeks the combination of the two
    enantiomer pairs making up cyhalothrin itself still predominated.
    Cyhalothrin was degraded on cabbage leaves to polar compounds that
    could be converted to organosoluble materials by acid hydrolysis.
    1RS-cis- and 1RS-trans-3-(ZE-2-chloro-3,3,3-trifluoroprop-
    1-enyl)-2,2-dimethylcyclopropanecarboxylic acids were the major
    hydrolysis products, accounting for approximately 8 percent of the
    radioactivity present (Curl & Leahey, 1983).

         A cabbage plant was sprayed eight times at weekly intervals with
    14C-cyclopropyl-labelled cyhalothrin, prepared as an aqueous dilution
    of a 10 percent E.C. formulation, at a rate of 25 g a.i./ha. The plant
    was left exposed to all weather conditions without shelter. One week
    after the final spray, total radioactive residues in the outer leaves
    and in the heart were 1.13 and 0.003 mg cyhalothrin equivalents/kg,
    respectively, equivalent to 0.44 mg/kg on a whole cabbage basis; 80
    percent of the radioactive residue in the outer leaves was unchanged
    cyhalothrin and the pattern of metabolism was the same as for a single
    application. The effects of photoisomerization were less marked in
    this study than in the one involving the single application, probably
    because most of the residues resulted from the final spray (Curl &
    Leahey, 1983).

         Evidence for the fate of the alcohol part of the molecule after
    ester hydrolysis was provided by studies on the structurally-similar
    compound cypermethrin, which were reviewed by the 1979 meeting and in
    which 14C-benzyl-labelled material was used. In outdoor studies on
    lettuce and apples, cypermethrin itself was still the dominant part of
    the residue after three weeks. On apple fruit and lettuce, most of the
    remainder of the radioactivity was present as polar materials, which
    individually were in too small amounts for detailed study. On apple
    leaves, compounds identified included 3-phenoxybenzoic acid,
    3-(4-hydroxyphenoxy)benzoic acid, 3-phenoxybenzaldehyde and
    3-phenoxybenzyl alcohol, either free or as conjugates.

         Samples of apples and peaches from trials in Japan have been
    analysed for residues of cyhalothrin, 3-phenoxybenzoic acid,
    3-(4-hydroxyphenoxy)-benzoic acid and 1RS-cis-3-(Z-2-chloro-
    3,3,3-trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylic acid
    (HCVA). In all cases, residues of the metabolites were very much
    smaller than those of cyhalothrin (Table 4) (Sapiets, 1984d; Swaine,
    Sapiets et al., 1983a, h).


        TABLE 4.  Cyhalothrin and Metabolite Residue in Apples and Peaches, Japan 1

                                                                                                                 

                                                                     Residue (mg/kg)
    Crop           Interval last                                                                                 
                   application to      Cyhalothrin         HCVA        3-phenoxy-       3-(4-hydroxyphenoxy)-
                   sampling                                            benzoic acid     benzoic acid
                   (days)
                                                                                                                 

    Apple               7                 0.16             0.02          <0.02             <0.05
                       14                 0.14            <0.01          <0.02             <0.05
                       21                 0.13             0.01          <0.02             <0.05

                        7                 0.16             0.04          <0.02             <0.02
                       14                 0.09             0.02          <0.02             <0.02
                       21                <0.02            <0.01          <0.01             <0.02

    Peach               7                 0.30             0.05          <0.02             <0.02
                       14                 0.25             0.08          <0.02             <0.05
                       21                 0.12             0.03          <0.02             <0.02

                        7                 0.30             0.07           0.02             <0.02
                       14                 0.22             0.03          <0.02             <0.02
                       21                 0.12             0.02          <0.02             <0.02
                                                                                                                 

    1  All trials done in 1982 using a 5 percent W.P. formulation
    
    In Soil

         At residue levels that are likely to occur under normal field
    conditions, cyhalothrin is degraded rapidly in soil. When a sandy loam
    soil was treated with 14C-cyclopropyl-labelled cyhalothrin, only 28
    percent of the recovered radioactivity was present as cyhalothrin
    after five weeks incubation under aerobic conditions; 30 percent was
    evolved as 14C-labelled carbon dioxide and 3.5 percent of the
    recovered radioactivity was due to 1RS-cis-3-(Z-2-chloro-3,3,3-
    trifluoroprop-1-enyl)-2,2-dimethylcyclopropane-carboxylic acid.
    Approximately 19 percent of the radioactivity was not extracted using
    acetonitrile at room temperature followed by soxhlet extraction with
    aqueous acetonitrile (Bewick & Zinner, 1981).

         Using soil thick-layer descending chromatography in three soils,
    cyhalothrin was shown to have low mobility in soil which was
    considerably less than that of atrazine (Stevens & Poole, 1981).

    In Water

         14C-cyclopropyl-labelled cyhalothrin was incubated with river
    water/sediment mixtures contained in quartz flasks. The flasks were
    either exposed to sunlight or were maintained under dark conditions by
    covering them with aluminium foil. In the dark, degradation of
    cyhalothrin was slow (over 80 percent unchanged after 32 days).
    However, when exposed to sunlight the cyhalothrin degraded with a
    half-life of approximately 20 days in both river water/sediment
    mixtures. The rate at which the parent compound was lost from the
    aqueous phase was, however, much more rapid than its rate of
    degradation in the whole water/sediment system. This was due to the
    ready absorption of cyhalothrin onto the sediment. The major
    degradation process was simple ester cleavage of the molecule,
    producing 1RS-cis- and 1RS-trans-3-(ZE-2-chloro-3,3,3-
    trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylic acids. After
    32 days irradiation, the compounds together represented 36 to 47
    percent of the radioactivity applied to the water/sediment systems.
    Some photoisomerization also occurred (Hall & Leahey, 1983).

    In Processing

         Cyhalothrin residues on cabbage are present mostly in the outer
    leaves. Therefore, the extent to which these outer leaves are removed
    before consumption has a major bearing on residues on cabbage at the
    point of consumption. In a field residue trial in the United Kingdom,
    cyhalothrin residues were found to be mainly in the seven outermost
    leaves (Sapiets, 1984b).

         In the cabbage metabolism work reviewed above, one week after the
    last of eight weekly sprays of 25 g a.i./ha, total radioactive
    residues in the outer leaves and in the hearts were 1.13 and 0.003 mg
    cyhalothrin equivalents/kg, respectively, equivalent to 0.44 mg/kg on
    a whole cabbage basis. Eighty percent of the radioactivity in the
    outer leaves was due to unchanged cyhalothrin (Curl & Leahey, 1983).

         Cyhalothrin levels on cabbage treated in Japan and from which
    leaves had been stripped before the crop was submitted for analysis
    were also extremely small (<0.01 mg/kg) (Swaine et al., 1983g).

         A comparison of cyhalothrin residues from two concurrent trials
    with the same 10 percent E.C. formulation, applied at the same rates
    in the same location in Spain on Chinese cabbage, from which outer
    leaves were not stripped, and on common cabbage, from which leaves
    were stripped before the crop was submitted for analysis, showed very
    much larger residues in the former (Table 5) (Sapiets, 1984a,e).

    METHODS OF RESIDUE ANALYSIS

         The crops were prepared for analysis by mincing or chopping until
    a homogeneous sample was obtained. For small fruits the whole sample
    was prepared; large vegetables, e.g. cabbage, were quartered and
    opposite quarters taken. Samples were extracted using 50 percent
    acetone in hexane and the extracts washed with water. Co-extractives
    were removed by liquid-liquid partition chromatography where necessary
    (crops requiring this clean-up include cabbage). All crops were
    cleaned up using Florisil adsorption chromatography. Final
    quantitative determination of cyhalothrin residues was by gas-liquid
    chromatography, using electron-capture detection. The limit of
    determination for total cyhalothrin isomers is 0.01 mg/kg.

         An internal standard procedure was used for the quantitative
    measurement of residues. The internal standard compound, a synthetic
    pyrethroid analogue in which a bromine atom is substituted for the
    chlorine atom on the vinyl side chain, was added to each sample prior
    to extraction. The response ratio of cyhalothrin to internal standard
    in the final extract of each sample was used for quantitative
    measurement of residues. The use of the internal standard allows the
    size of the sample aliquot processed through the method to be reduced
    without loss of accuracy. In addition, as the recovery of pyrethroid
    is effectively monitored for each sample, the precision of the assay
    is significantly improved using this procedure. Calibration curves
    plotted for amount of cyhalothrin versus response ratio of cyhalothrin
    to internal standard gave linear regression lines (correlation
    coefficient r > 0.99) with an intercept passing through the origin
    (Sapiets & Swaine, 1983).

    APPRAISAL

         Cyhalothrin is a new photostable synthetic pyrethroid insecticide
    and acarcide with a level of activity, demonstrated by required dose
    rates, between deltamethrin and the other related compounds permethrin
    and cypermethrin. Since it is not systemic, residue levels depend on
    the amount applied and the efficiency of application.


        TABLE 5.  Cyhalothrin Residues on Cabbage and Chinese Cabbage, Spain 1

                                                                                                                                  

                                   Application
                                                                                              Residues (mg/kg)
    Crop                Rate          Volume          No.       Interval last                                                     
                        (g a.i./ha)   of spray                  spray to            R157836        Rl19321        Total
                                      (1/ha)                    sampling (days)                                   Cyhalothrin
                                                                                                                                  

    Cabbage (wrapper      20           300            4               0             0.03           0.02           0.04
    leaves stripped                                                   3             0.01           0.01           0.02
    off before                                                        7             0.01           0.01           0.02
    analysis)
                          40           300            4               0             0.02           0.01           0.03
                                                                      3             0.04           0.02           0.06
                                                                      7             0.01           0.01           0.01

    Chinese cabbage       20           300            4               0             0.44           0.31           0.75
    (wrapper leaves                                                   3             0.25           0.18           0.43
    not stripped off                                                  7             0.18           0.13           0.32
    before analysis)
                          40           300            4               0             0.58           0.43           1.0
                                                                      3             0.28           0.21           0.49
                                                                      7             0.28           0.20           0.48
                                                                                                                                  

    1  All trials done in 1983 using 10 percent E.C formulation
    
         The uses considered by the meeting were on pome fruit and cabbage
    only. The proposed GAP is up to 100 mg/l (0.01 percent) in the spray,
    100 g a.i./ha, per application on apples and pears with a 14-day
    interval between the last application and harvest. Rates are
    approximately 10-20 g a.i./ha on cabbage, up to six applications are
    used with an interval of 2-4 days between the last application and
    harvesting.

         The meeting noted that the maximum rate of application used in
    the trials on pome fruit was not well defined. The highest
    concentration used was 80 mg/l in the spray; this sprayed to 'run-off'
    might equate with a high-volume spray of 2 000 l/ha, i.e. 160 g
    cyhalothrin/ha. Initial deposits from a single application indicated
    that residues up to 0.5 mg/kg could be expected; this decreased to
    about 0.2 mg/kg in 14 days. In several other trials, at lower spray
    concentrations, residues did not exceed 0.2 mg/kg as initial deposits,
    even when very high volumes were applied and the total rate of
    application approached 160 g a.i./ha. Although on some occasions some
    residues diminished with time, several trials showed virtually no
    decrease in residues over the first 14 days after application. The
    meeting concluded that more attention should be given to initial
    deposits and that residues could reach 0.5 mg/kg, especially at the
    higher rates and volumes needed to control fruit tree red spider mite.
    This estimate of the maximum residue level was considered suitable for
    establishing a temporary MRL and should be reviewed in 1986 in the
    light of more residues data.

         The data on cabbage were considered inadequate for the estimation
    of a maximum residue level.

    RECOMMENDATIONS

         The following maximum residue level was estimated and recommended
    as suitable for use as a temporary MRL.

                                                                      

                   Temporary MRL       Preharvest interval on which
                   (mg/kg)             recommendation is based (days)
                                                                      

    Pome fruit     0.5                               14
                                                                      

    FURTHER WORK OR INFORMATION

    Required (by 1986)

    1.  Further residues data on pome fruit.

    2.  Further information on GAP in use of cyhalothrin on pome fruit.

    REFERENCES

    Bewick, D.W. & Zinner, C.K.J. Cyhalothrin: degradation in soil. Report
    1981      No. RJ 0203B submitted by ICI Plant Protection Division to
              FAO. (Unpublished)

    Curl, E.A. & Leahey, J.P. Cyhalothrin: metabolism in cabbage. Report
    1983      No. RJ 0308B submitted by ICI Plant Protection Division to
              FAO. (Unpublished)

    Hall, J.S. & Leahey, J.P. PP564: degradation on apples. Report No. TMJ
    1979      1728B submitted by ICI Plant Protection Division to FAO.
              (Unpublished)

    Hall, J.S. & Leahey, J.P. Cyhalothrin: fate in river water. Report No.
    1983      RJ 1983 0320B submitted by ICI Plant Protection Division to
              FAO. (Unpublished)

    Sapiets, A. Cyhalothrin: residue levels on chinese cabbage from 1983
    1984a     trials in Spain. Report No. M3749B submitted by ICI Plant
              Protection Division to FAO. (Unpublished)

    Sapiets, A. Cyhalothrin: residues on cabbage from 1983 trials in the
    1984b     United Kingdom. Report No. M3733B submitted by ICI Plant
              Protection Division to FAO. (Unpublished)

    Sapiets, A. Cyhalothrin: residue levels on crop samples taken from
    1984c     trials during 1982-84. Report No. M3791B submitted by ICI
              Plant Protection Division to FAO. (Unpublished)

    Sapiets, A. Cyhalothrin: residue levels of the major metabolites in
    1984d     apple, peach and cabbage from 1982 trials in Japan. Report
              No. M3708B submitted by ICI Plant Protection Division to
              FAO. (Unpublished)

    Sapiets, A. Cyhalothrin: residue levels on cabbage from 1983 trials in
    1984e     Spain. Report No. M3790B submitted by ICI Plant Protection
              Division to FAO. (Unpublished)

    Sapiets, A. & Swaine, H. The determination of residues of cyhalothrin
    1983      in crops - a gas-liquid chromatographic method using an
              internal standard. ICI Plant Protection Division Residue
              Analytical Method (PPRAM) NO. 70.

    Stevens, J.E.B. & Poole, N.J. Cyhalothrin: leaching on soil
    1981      thick-layer chromatograms. Report No. RJ 0206B submitted by
              ICI Plant Protection Division to FAO. (Unpublished)

    Swaine, H. & Sapiets, A. Cyhalothrin: storage stability of frozen crop
    1984      samples. Report submitted by ICI Plant Protection Division
              to FAO. (Unpublished)

    Swaine, H., Sapiets, A. & Burke, S. Cyhalothrin residues in apples
    1983a     from Japan in 1982. Residue Data Report No. PP563B003
              submitted by ICI Plant Protection Division to FAO.
              (Unpublished)

    Swaine, H., Sapiets, A. & Burke, S. Cyhalothrin residues in apples
    1983b     from South Africa in 1982-3. Residue Data Report No.
              PP563B008 submitted by ICI Plant Protection Division to FAO.
              (Unpublished)

    Swaine, H., Sapiets, A. & Burke, S. Cyhalothrin residues in apples
    1983c     from Spain in 1982. Residue Data Report No. PP563B007
              submitted by ICI Plant Protection Division to FAO.
              (Unpublished)

    Swaine, H., Sapiets, A. & Burke, S. Cyhalothrin residues in apples
    1983d     from UK in 1982. Residue Data Report No. PP563B001 submitted
              by ICI Plant Protection Division to FAO. (Unpublished)

    Swaine, H., Sapiets, A. & Burke, S. Cyhalothrin residues in pears from
    1983e     Cyprus in 1982. Residue Data Report No. PP563B005 submitted
              by ICI Plant Protection Division to FAO. (Unpublished)

    Swaine, H., Sapiets, A. & Burke, S. Cyhalothrin residues in cabbage
    1983f     from USA in 1982. Residue Data Report No. PP563B006
              submitted by ICI Plant Protection Division to FAO.
              (Unpublished)

    Swaine, H., Sapiets, A. & Burke, S. Cyhalothrin residues in cabbage
    1983g     from Japan in 1982. Residue Data Report No. PP563B002
              submitted by ICI Plant Protection Division to FAO.
              (Unpublished)

    Swaine, H., Sapiets, A. & Burke, S. Cyhalothrin residues in peaches
    1983h     from Japan in 1982. Residue Data Report No. PP563B004
              submitted by ICI Plant Protection Division to FAO.
              (Unpublished)

    Swaine, H., Sapiets, A. & Burke, S. Cyhalothrin residues n pears
    1984      from South Africa in 1982-3. Residue Data Report No.
              PP563B013 submitted by ICI Plant Protection Division to FAO.
              (Unpublished)


    See Also:
       Toxicological Abbreviations
       Cyhalothrin (EHC 99, 1990)
       Cyhalothrin (ICSC)
       Cyhalothrin (WHO Food Additives Series 53)
       Cyhalothrin (WHO Food Additives Series 45)
       CYHALOTHRIN (JECFA Evaluation)
       Cyhalothrin (Pesticide residues in food: 1984 evaluations)
       Cyhalothrin (UKPID)