GUAZATINE       JMPR 1978


    Chemical Name



         bis(guanidino-8-octyl) amine guanidated

         The following names refer to guazatine triacetate: EM
         379; MC25; PN25; P3290; E116335.

         Panoctine (R); Panolil(R), Pastulat(R).

    Structural formula

            NH                      NH
             "                       "


    Other information on identity and properties

         Guazatine is used as the triacetate. The commercial product,
    which has been in production since about 1974, consists of a
    standardised mixture of the acetates of guazatine and related
    diguandines including guanidated 1,8-diamino-octane and higher
    oligomers such an guanidated trioctylenetetramine. 82-84% of the
    amino functions present are converted to guazatine groups. It is
    not possible to isolate the oligomers or to produce the pure
    guazatine by industrial processes but all oligomers have comparable
    biological activit, and are considered together as active
    ingredients (KenoGard 1978).

    The following properties refer to the acetate(s).

    Molecular Weight:   535 (range for components of technical material

    State:              As water solution: milky yellowish brown,
                        somewhat viscous

    Density:            1.060 g/cc

    pH:                 as 2% solution in water 6 ± 1

    Flash point:        >100°C

    Volatility:         Not volatile

    Melting point:      No precise melting point owing to the presence of
                        various guanidines, but melts gradually
                        starting at approximately 95°C

    Boiling point:      Decomposes above 120°

    Solubility (g/100g at 25°C):

    water               >300
    dimethylformamide   approx 50
    dimethyl sulphoxide approx 100
    ethanol             approx 200
    methanol            >300
    xylene              very low
    hydrocarbons        very low

    storage stability:  formulations stable at normal temperature for more
                        than 2 years

    Impurities in the technical material

         Information was provided on the quality and composition of the
    technical material which has been standardised by the only
    manufacturer. The standardised technical material was used in all
    toxicological metabolism and residue studies (KenoGard 1978).


         (1) Seed dressings containing 20-35% guazatine alone and in
             combination with other seed treatment fungicides.

         (2) Sugar cane dipping preparation containing 60% guazatine.

         (3) Seed potatoes spray containing 60% guazatine.

         (4) Citrus spray/dip containing 60% guazatine.



    Absorption, distribution and excretion

         A male rat was orally treated with guazatine, labelled with
    both 3H in the octyl moiety and 14C in the guanidino moiety.
    Within 72 hours about 15% of the administered 14C radioactivity
    were excreted in the urine and about 65% in the faeces, whereas
    approximately 42% and 39% of the 3H activity were eliminated in

    the urine and faeces respectively. After 3 days the body still 
    contained about 4% of the 14C-dose and 12.5% of the 3H-dose. The 
    14C/3H ratios in urine and faeces indicate that the compound 
    undergoes biotransformation. The TLC analysis resulted in one major 
    and a few minor components in urine and two major components in 
    faeces. None of the metabolites were identified (Leegwater, 1975).

    Effects on other biochemical aspects

         The acute pharmacodynamic effects on the vascular system were
    studied in cats treated with single or repeated doses of EM 379
    (composition of the formulation unknown) by the intravenous and
    intraduodenal route. The application produced marked dose-related
    depression of blood pressure when applied in i.v. doses of 0.5-8
    mg/kg. The fall in blood pressure was accompanied by an increase in
    heart and respiratory rate and doses of 2 mg/kg and above caused
    additionally pupillary dilation, urination and hind limb movement.
    Cumulative i.v. doses of 8-16 mg/kg led to death of the
    experimental animal. Similar effects were obtained after
    intraduodenal application of the test compound (Davis et al.,


    Special studies on reproduction and teratogenicity


         Guazatine techn. grade; (54.8% w/w ai.i. in water) was fed to
    groups of 10 male and 20 female rats at dietary levels of 0, 60 and
    200 ppm for three successive generations (2 litters per

         A teratogenicity study was carried out at the same time with
    F3C and F3b-litters. Additionally a 4-week feeding study was
    conducted using F3b-litters. The reproduction study revealed no
    abnormal findings with respect to general condition, behaviour,
    body weights and fertility of the dame or birth weight and survival
    rate of the pups. No malformations were observed in any of the

         The results of the teratogenicity study showed no
    abnormalities as regards the dams. Implantation losses and
    resorptions did not significantly differ in the various groups.  At
    200 ppm foetal weight was slightly reduced in the F4a-litters. No
    visceral or skeletal anomalies were found, but in the F3c
    generation a tendency to retardation in bone development was

         The 4-week feeding study revealed no treatment-related
    abnormal findings as regards the general health, growth and food
    consumption. A dose-related increase of the kidney weights was
    found in both sexes. The relative thymus weights were also

    increased in all treated animals, dose-related in females, without
    dose-relationship in males. These changes in organ weight were not
    accompanied by gross or microscopic morphological alterations (Til
    et al., 1976a).

    Special study on carcinogenicity


    See under long term studies.

        Acute toxicity


    Species        Sex       Route           LD50          References

    Rat            M F       oral           227            Anonymous, 1973a

    Rat            M F       i.p.           53             De Groot, 1976a

    Rat                      inhalation     11 mg/m3       Kruysse and Immel, 1976

    Cat            M F       oral           382            De Groot, 1976b

    Rabbit         M F       dermal (24h)   2800           van Beek et al., 1976

    Fish (carp)                             2.9 ul/l       Spanjers and Til, 1974a
                                            (LC50 96h)

    (guppy)                                 0.54 ul/l      Spanjers and Til, 1974b
                                            (LC50 96h)
    Short term studies


         Groups of 10 male and 10 female rats were maintained on a diet
    containing 0, 60 and 200 ppm guazatine (techn. grade; 54.8% w/w
    a.i. in water) for a period of 90 days. The treatment did not
    affect behaviour, mortality, body weight gain and food consumption.
    The values of haematology, clinical chemistry and urine analysis
    were within normal limits. No distinct differences in the relative
    organ weights existed between the various groups. The gross and
    microscopic examination revealed no pathological findings which
    could be attributed to the ingestion of the test compound
    (Sinkeldam and van der Heiyden, 1974).

         Groups of 10 male and 10 female rats were fed with guazatine
    (techn. grade; 54.8% w/w a.i. in water) at dietary levels of 0 and
    800 ppm. After 6 weeks of feeding the guazatine level was increased
    to 1200 ppm for the last 7 weeks of the study. The treatment had no
    effect on general condition, behaviour and survival rate. The
    haematological and biochemical examinations revealed no abnormal
    values. Slight reduced body weights were observed in both sexes
    accompanied by slightly diminished food consumption in the treated
    male rats. Besides a lower specific gravity of the urine in the
    treated females no abnormal findings were observed. The relative
    organ weights of the testicles and adrenals were increased in males
    compared to the control animals. No abnormal pathological gross
    autopsy or microscopic findings were observed, except for one type
    of thyroid lesion found in two females (out of total 10) in the
    test group, the abnormal thyroids were increased in weight and
    contained small follicles (Til and Feron, 1975).

         A 13-week feeding study was performed with groups of 10 male
    and 10 female rats maintained on a diet supplemented with 0 and
    1500 ppm guazatine (techn. grade; 40% w/w a.i. in water) for the
    first four weeks of the study and 2000 ppm for the last nine weeks
    of the experiment. General health, behaviour and mortality was not
    affected by the treatment, whereas the treated animals showed
    reduction in body weight and food consumption. Results of
    haematological clinical biochemistry and urine examinations were
    within normal limits. The kidney function test revealed a slight
    decrease in specific gravity of urine in test group. At 1500/2000
    ppm increased relative organ weights of the kidney, liver and heart
    (females only) were found, whereas; the mean relative thyroid
    weights were reduced in both sexes. Gross autopsy examination did
    not reveal pathological changes, the histopathological examination
    however showed hyperplastic, epithelium of the excretory ducts of
    the parotid salivary glands, often accompanied by infiltrates of
    inflammatory cells. 6 out of 10 male rats and 6 out of 10 female
    rats showed these changes compared to none in the control group
    (Til and Hendriksen, 1976b).


         A 13-week comparative study with guazatine (techn. grade., 40%
    w/w a.i. in water) and the structurally related compound
    guanethidine, a pharmaceutical against hypertension was carried out
    with groups of 30 male and 30 female mice. The diet was
    supplemented with either 0 and 50 ppm guanethidine or 0 and 500 ppm
    guazatine. The feeding did not affect the health condition,
    behaviour and the weight gain of the test animals. A significant
    decrease in blood pressure was produced in the guanethidine fed
    males after 4 weeks of experiment, whereas no marked changes in
    blood pressure could be observed after guazatine treatment of mice
    (Feron and Mullink, 1977).


         In a 18-day feeding experiment with egg-laying hens the
    animals were fed ad libitum with seed that had been treated with
    2 ml 40% panoctine/kg seed (normal use level) (40% w/v a.i. in
    water) and 4 ml 40% panoctine/kg seed. The test compound showed a
    marked repellent effect on poultry causing weight loss and
    reduction of egg-production (Kivimae 1973). Similar results were
    obtained in a feeding study with pigeons and pheasants (Anonymous,


         Groups of 4 male and 4 female dogs were fed with a diet
    supplemented with 0, 60, 200 and 300 ppm guazatine (techn. grade,
    54.8% w/w a.i. in water) for two years. 26 weeks after the
    beginning of the study the high dietary level was increased to 600
    ppm until the end of the experimental period. The feeding did not
    influence the general condition, behaviour, growth rate and food
    consumption. The results of the haematologic and clinical chemistry
    determinations fall within normal limits, except for a slight
    decrease in the white blood cell counts at most stages of the
    experiment in the 300/600 ppm group compared to the control. The
    urinary findings did not suggest any changes due to treatment. In
    the kidney function and liver function tests normal values were
    obtained. The only alteration in relative organ weight was found in
    the 300/600 ppm group where female animals showed increased
    relative ovary weights. No gross pathological or histopathological
    findings were discovered (Reuzel et al., 1976).

    Long term studies


         Groups of 60 male and 60 female rats were maintained on a diet
    containing 0, 69 20, 60 and 200 ppm guazatine (techn. grade; 54.8%
    w/w a.i. in water) for two years. After a few months of feeding the
    6 ppm group was discarded. The treatment did not adversely affect
    the general condition survival rate and food intake of the test
    animals. In females treated with dietary levels of 20-200 ppm a
    reduced body weight of 10-20% was noted during month 22 and 24.
    Since this effect showed no dose dependency and was noted only in
    females at the end of the experiment it was not considered to be
    related to the treatment. No dose-related alterations in the
    haematological and biochemical blood parameters were found, nor did
    the urine analysis and kidney nor function test show abnormal
    results. Some differences in the relative organ weights compared to
    control were observed in the treated animals but no
    dose-relationship was evident. The macroscopic and microscopic
    examination of the control and the 200 ppm-group did not reveal
    organ lesions that could be attributed to treatment in
    histopathological alterations of the parotidasalivary lands were

    found. The tumour incidence was similar in the control and treated
    groups (Til et al., 1976).


         Radioactive labelled guazatine, when applied as a single oral
    dose to rats is excreted at about 80% within 72 hours after
    application. There is no indication of tissue accumulation.
    Although no experimental studies were available to determine the
    exact metabolic pathway it can be assumed that the absorbed
    components of low molecular weight may be degraded further to
    normal body constituents.

         Results of short-term and 2-year toxicity studies were
    available. These studies showed a no effect level of 200 ppm in
    rats and dogs. In a three generation study no effects on
    reproduction and on teratogenicity were observed. There were no
    differences between control and treated groups with respect to
    tumour incidence.


    Level causing no toxicological effect

    Rat:      200 ppm, (54.8% active ingredient as acetate in water)
              equivalent to 5 mg/kg body weight of the active

    Dog:      200 ppm (54.8%  active ingredient as acetate in water) in
              the diet equivalent to 3 mg/kg body weight of the active

    Estimate of acceptable daily intake for man

         0 - 0.03 mg active ingredient as acetate/kg body weight



         Guazatine is a fungicide developed in about 1968 for the
    control of most cereal seed diseases, including those in rice, rice
    blast, pineapple disease of sugar cane and a number of disease in
    seed potatoes.

         In recent years it has been shown to be particularly effective
    against fungal diseases of citrus especially Penicillium, Diploida,
    Alternaria and Geotrichium which cause serious wastage of citrus
    fruit during transport, storage and marketing (Tugwell, 1977,
    CascoGard 1976, Hartill et al., 1977).

         Reports have confirmed the efficacy of guazatine against a
    number of fungal diseases of bananas, coffee, soybeans and flower
    bulbs. A list of uses is given in Table 1. The application rates
    are those currently recommended or under investigation (CascoGard


         A limited amount of information was available from trials
    designed to determine the level and fate of guazatine residues in
    raw agricultural commodities following treatment.

         Thornberg (1977) reported the results of analysis of 39
    samples of raw cereals including barley (13), oats (5), rye (9) and
    wheat (12) from field trials in Sweden, Germany and South Africa.
    These represented grain collected from crops grown from seed
    treated with guazatine acetate at the rate of 60-120g/100 kg of
    seed. The grain was collected 4-10 months after the seed was sown.
    The analytical method used had a limit of determination of 0.1 mg/kg.
    No guazatine was found in any of the samples, nor was any residue 
    detected in 20 samples of straw from the same trials.

         Analysis of potato tubers from crops grown from seed potatoes
    treated with guazatine 5 months previously revealed no guazatine
    (< 0.05 mg/kg).(Kemanord AB, 1976).

         Pineapple fruit, shells and leaves from plants grown from
    seedpieces that had been dipped in guazatine solution 21 months
    previously were found to contain no detectable residues (< 0.1
    mg/kg) (Thornberg 1976). Sugar cane, bagasse, molasses and raw
    sugar from a crop or sugar cane grown from setts (planting
    cuttings) treated with guazatine at a concentration of 100 and 250
    mg/l contained no detectable residues (Kemanobel Research
    Laboratory 1976).


         The Israeli Ministry of Agriculture (Resnick and Greenberg,
    1977) reports the results of a trial in which "Shamouti" oranges
    were dipped experimentally in aqueous solutions and in wax
    emulsions containing guazatine at concentrations ranging from 5 to
    40 g/l. This is up to 10 times higher than is recommended for
    post-harvest dips. It is recognized that fungicides applied in wax
    are much less effective than when applied from a water-dip prior to

         The residues were determined by the method of Mori (1975). The
    results are indicated in Table 2.

         Fruit from two of the treatments (the lowest and highest
    concentrations) were examined 1, 10 and 20 days after treatment to
    determine the degree of chemical breakdown. As indicated in Table
    3 there was no loss during 20 days (the temperature of storage was
    not given).

         In two trials carried out in Japan (More, 1975) mandarin
    oranges ("Satsuma" variety) were sprayed on the trees with
    guazatine solution (500 mg/l) at the rate of 1000 l/ha yielding the
    residue data reported in Table 4. The concentration in the flesh or
    juice was less than 1/10 of that in the peel.

         In a trial in which radio-labelled guazatine was applied to
    Jaffa oranges from Israel, Bodin (1978) studied the uptake,
    penetration and persistence of guazatine residues on oranges stored
    up to 50 days at 4°C. Separate lots of oranges were drenched with
    aqueous solutions of guazatine acetate labelled with both 14C and
    3H at concentrations of 0.1% and 0.2% at 12-18°C for 30-60
    seconds. The dipped fruit was dried and some was subjected to
    degreening with ethylene gas. All fruit was then waxed with a
    commercial citrus wax containing thiabendazole before being dried
    and stored at 4°C. Duplicate samples were analysed

        TABLE 1. Use pattern of guazatine.


    Crop                Pest                     Concentration            Method of application

    1. Wheat, oat,      Fusarium spp.            60-80 g/100 kg           Seed dressing machines
       barley, rice,    Tilletia spp.            of seed                  Seed dusters
       rye              Septoria nodorum

    2. Sugar cane       Pineapple disease        100 mg/l (hot)           Dipping tank
                        (Ceratocystis            250 mg/l (cold)

    3. Potatoes         Rhizoctonia solani      15-30 g/tonne            Spray at time of
                        Phoma spp.                                        sorting

    4. Citrus           Penicillium spp.         100-500 mg/l             Dipping tank
                        Alternaria spp.          1-2 g/1                  Wax-treatment spray

    5. Rice             Foliar diseases          ?                        Broadcast spray
    by liquid scintillation measurement after 0, 1, 8, 24 and 50 days
    storage. Before analysis each orange was separated into yellow peel,
    white and pulp. The average weight of each fruit was 220 g and the
    proportion of peel, white and pulp was 25%, 14% and 61% respectively.
    The guazatine content of the separate tractions, calculated from the
    scintillation counts, is shown in Tables 5 and 6, which show the range
    and mean residues in the three fractions following treatment at the
    two concentrations. The mean was derived from separate values
    determined at 0, 1, 8, 24 or 50 days after treatment.

    TABLE 2. Guazatine residues in shamouti oranges dipped post-harvest.


    a.i. in water or wax,         Date of             Residue, mg/kg
    mg/kg                         treatment

    20,000 (wax)                  11.1.77             11.0      9.0
    40,000 (wax)                  11.1.77             13.0      12.0

    5,000 (water)                 11.2.77             1.5
    5,000 (wax)                   11.2.77             1.5
    10,000 (wax)                  11.2.77             7.0
    20,000 (wax)                  11.2.77             8.0

    2,500 (water)                 24.2.77
    5,000 (wax)                   24.2.77             1.5
    5,000 (wax)                   24.2.77             3.0
    10,000 (wax)                  24.2.77             6.0
    20,000 (wax)                  24.2.77             9.0

         It will be apparent that closely comparable results were obtained
    from the measurement of the 14C and 3H labels, indicating that
    minimal decomposition or metabolism has occurred. From the 250
    separate analyses in the original data there is great variation
    between fruits. The variation could well be greater in fruit treated
    in commercial packing houses and therefore further studies under
    packing house conditions are required. The degreening treatment had no
    significant influence on the residue content. There was a tendency for
    a slight decrease in the residue concentration in the peel during 50
    days at 40°C, indicating some diffusion into the pulp.

         Preliminary results were available from trials now in progress in
    Australia. When Valencia oranges were dipped under laboratory
    conditions in guazatine solutions ranging from 140 mg/l to 500 mg/l
    the residue in the whole fruit was as follows (Ahmed, 1978):

                   Dip                 Residue
                   Concentration       (mg/kg)

                   140                 0.22

                   260                 0.45

                   290                 0.5

                   500                 0.9

    TABLE 3. Stability of guazatine residues in stored shamouti oranges.


    a.i., mg/kg         1 day after         10 days after       20 days after
                        treatment           treatment           treatment

    5,000               1,2; 1,2; 1,5       -                   -

    20,000              11; 9.0; 10.0       12.0; 9.0; 10.0     11.0; 8.0; 10.0
         Fruit from commercial trials where guazatine had been applied by
    (a) dipping and (b) flooding were found to contain guazatine residues
    as shown in Table 7.


    In animals

         The fate of guazatine in rats has been described under the
    Section "Biochemical Aspects" (Leegwater 1975). No other information
    was available to demonstrate the level and fate of residues in
    livestock or foods of animal origin following the feeding of
    guazatine-treated seed or dried pulp from guazatine-treated citrus.

         Kivimäe (1973) reported an extensive and complex trial carried
    out at the Royal Agricultural College of Sweden in which hens and
    cocks were fed a mixture of wheat and barley that had been treated
    with guazatine seed dressing at normal and double dosage. The trial
    was designed to determine feed consumption and effect on weight,
    egg-laying, fertilization and hatchability of the eggs. Many of the
    chickens starved to death rather than eat the treated seed. After a
    period of 18 days on the treated feed the chickens were given a choice
    of treated or untreated grain and they avoided the treated seed

    completely. The effect on weight and other parameters was directly
    related to the starvation. No attempt was made to determine whether
    the chickens accumulated any guazatine from the small amount of seed
    consumed but post-mortem examinations were carried out to determine
    the cause of death of those that did not survive the experiment.

    TABLE 4. Residues of guazatine in satsunya mandarin fruit (Japan).


    LOCATION            Concn      Rate       No. of     Pre-harvest            Residues (mg/kg)
                        mg/l       l/ha       sprays     intervals       flesh       peel       juice

                        0          0          0          -               < 0.05      < 0.05     < 0.05
    AICHI               500        500        1          3               0.18        2.7        -
    PREFECTURE          500        500        1          8               0.11        1.1        0.06
                        500        500        1          13              0.07        1.1        -
                        500        500        1          18              < 0.05      0.5        -

                        0          0          0          -               < 0.05      < 0.05     < 0.05
    SHIZUCKA            500        500        1          3               0.06        1.5        -
    PREFECTURE          500        500        1          8               0.05        2.1        0.05
                                              1          13              0.05        1.5        -
                                              1          18              < 0.05      1.1        -

    TABLE 5. Guazatine residues in stored oranges (normal moisture content) not degreened.

                                            Guazatine acetate, mg/kg

    Drench                        PEEL                WHITE               PULP

    14C                 Range     3.00 - 9.35         0.19 - 0.70         0.0019 - 0.00739

    0.1%                Mean      = 6.35              = 0.38              = 0.0336

    14C                 Range     12.0 -21.5          0.25 - 3.54         0.0307 - 0.3398

    0.2%                Mean      = 15.9              = 1.21              = 0.1306

    TABLE 5. (Cont'd)

                                            Guazatine acetate, mg/kg

    Drench                        PEEL                WHITE               PULP

    3H,                 Range     3.68 - 8.99         0.25 - 0.89         0.0106 - 0.0902

    0.1%                Mean      = 6.15              = 0.49              = 0.0346

    3H,                 Range     11.48-21.74         0.59 - 4.61         0.0259 - 0.4272
    0.2%                Mean      = 17.29             = 1.48              = 0.1315

    Untreated           Range     0.0068 - 0.0068     0.0061 - 0.0081     0.0038 - 0.0038

                        Mean      = 0.0068            = 0.0071            = 0.0038

    TABLE 6. Guazatine residues in stored oranges (normal moisture content) degreened.


                                               Guazatine acetate, mg/kg
    Drench                        PEEL                WHITE               Pulp

    14C                 Range     4.27 - 7.05         0.08 - 0.24         0.0202 - 0.0643

    0.1%                Mean      = 5.18              = 0.15              = 0.0422

    14C                 Range     12.15 - 18.80       0.27 - 0.98         0.0528 - 0.4118

    0.2%                Mean      = 14.44             = 0.59              = 0.1411

    3H                  Range     3.75 - 6.17         0.09 - 0.18         0.0067 - 0.0460

    0.1%                Mean      = 4.47              = 0.14               = 0.0240

    3H                  Range     12.34 - 22.55       0.35 - 1.99         0.0374 - 0.5242

    0.2%                Mean      = 14.92             = 0.89              = 0.1430

    TABLE 7. Guazatine residues in dipped or flooded citrus fruit


    Fruit                    Concentration    Method of         Guazatine residues
                             of bath,         Application            (mg/kg)
                             mg/l                               Peel          Whole fruit

    Valencia orange              250              dip           -             0.42

    Lemon                        250              dip           -             0.48

    Tangerine                    250              dip           -             0.48

    Valencia orange              500              dip           3.6           0.51

    Lemon                        500              dip           3.3           0.90

    Tangerine                    500              dip           5.5           0.83

    Valencia orange              500            flood           -             0.671/

    Lemon                        500            flood           -             0.761/

    Tangerine                    500            flood           -             0.931/

    1/ Held 7 days at 7.5°C before analysis.
         Svensson (1975) carried out trials to determine the effect on
    domestic poultry of seed dressings containing imazalil alone and in
    combination with guazatine. The fungicides were incorporated into a
    balanced layer-ration apparently at a level corresponding to the
    incorporation of treated seed as one of the components. The
    concentration was 600 mg of guazatine and 40 mg of imazalil per kg of
    feed. Imazalil had no effect on feed consumption, weight gain, egg
    production or hatchability. The group which received the ration
    containing guazatine refused to eat, lost weight heavily and within
    two weeks stopped laying. When they were returned to the base ration
    without guazatine they recovered weight and egg production. Lund
    (1973) carried out an experiment to investigate the degree of
    repellency of guazatine-treated seed to seed-eating birds. The
    experiment showed that guazatine had a strong repellent effect on
    pigeons and pheasants but no attempt was made to determine i,tether
    any residues resulted from the consumption of the seed which was

    In plants

         Bodin (1975) studied the distribution of radioactivity in wheat
    plants grown from seed that had been treated with radio-labelled
    guazatine. The plants were grown in pots in the glasshouse. At the end
    of 8.5 months the whole plants were harvested and divided into root,
    leaf, ear and stem. The radioactivity was measured by the method
    described by Peterson et al., (1969) in which the 14C and 3H 
    activity can be counted separately.

         A total of less than 1% of the 14C radioactivity applied to the
    seed was found in the whole wheat plant. About 8% of the 3H activity
    was found in the plant but virtually all in the roots. The absence of
    14C-activity in the ears at a detection limit of 0.01 mg/kg means
    that neither guazatine nor its metabolites is transferred to grain.
    There was clear evidence of at least partial metabolism of guazatine
    prior to incorporation into the plant tissue. Hydrolysis can give rise
    to urea or carbon dioxide. However, one study with radio-labelled
    material applied to oranges (described earlier, Bodin 1978) indicates
    that deposits on oranges remain virtually unchanged for 50 days at

    In soil

         Leegwater (1975) reported a study in which guazatine labelled
    with 3H in the octyl moiety and 14C in the guanidino moiety was used
    to observe the fate in a sample of sandy loam. An aliquot of
    radio-labelled guazatine was mixed with loam containing 20% water; the
    pH of an aqueous extract was 5.4 and the organic matter content was 7
    of the dry weight. The preparation was kept at room temperature (max
    28°C) for 7 days. At the end of this period about 83% of the 14C and
    about 50% of the 3H appeared to be tightly bound to the soil,
    particularly to the humus. About 8% of the 14C was extractable with
    water and about 2% was recovered as carbon dioxide. About 30% of the 
    3H was extractable with water and about 13% evaporated from the
    sample and could be trapped in water. It was presumed to be water
    formed by degradation.

         The Royal Institute of Technology, Stockholm (Anon. 1978) reports
    a study carried out in accordance with the German Biologische
    Bundesanstalt "Merkblatt 36" in 1978 in which the fate of guazatine in
    standard soil was measured by means of radiometry.  This showed that
    the guanidino carbon is converted to and released as carbon dioxide.
    No intermediate could be detected. This suggests a cleavage of the
    guanidino group producing amine and urea, followed by a further
    decomposition of the urea by urease. Deguanidation seems to be the
    rate-determining step. The study indicated that when guazatine was
    incorporated in soil at a concentration of 500 mg/kg, 50%
    decomposition occurred in 4 weeks at 20°C. it was concluded that
    guazatine was degraded extensively in soil.

    In processing and cooking

         The work of Bodin (1978) who treated oranges with radio-labelled
    guazatine indicated that the bulk of the deposit remains as a residue
    in the yellow peel and white pith of the orange. Only 2% of the
    deposit on the whole fruit is to be found in the pulp. It therefore
    follows that in the preparation of orange juice the bulk of the
    residue will remain in the skin and be discarded.

         No other information was available on the effect of processing or


         Mori (1975) developed a method of determining guazatine residues
    in mandarin oranges. It is based on extraction with butanol of the
    substrate which has been treated with picric acid to form guazatine
    picrate. The extract is hydrolysed with alkali at 160°C to form the
    corresponding triamine (di(8-amino-octyl)amine). The triamine is
    measured by gas chromatography using a nitrogen-thermionic detector.
    The limit of determination is said to be 0.05 mg/kg. The recovery of
    guazatine from oranges fortified at the 2 mg/kg level ranged from 87
    to 97%.

         Resnick and Greenberg (1977) used the same method to measure
    guazatine residues in organes treated with a wax emulsion containing
    guazatine. They report the recovery to be only 50% and the limit of
    determination 1-2 mg/kg.  Two Australian laboratories attempted to use
    this method without success (Snelson, 1978). The method has been
    modified by Thornberg (1978). The main modification appears to be that
    the triamine formed by alkaline hydrolysis at 160°C (autoclave) is
    extracted into benzene and converted to trifluoroacetamide by reaction
    with trifluoroacetic anhydride for determination by GC-MS using
    multiple-ion detection.

         Guazatine residues are usually firmly adsorbed to the substrate
    and care is needed to ensure complete extraction. The temperature of
    hydrolysis (160°C) is critical, as is the time of heating. The
    standard solution, which consists of a solution of the standardised
    technical material, has recently been shown to be unstable, the
    concentration decreasing when dilute aqueous solutions are stored in
    glass. Fresh solutions and silanised glassware should be used. After
    trifluoro-acetylation, the derivative is stable and readily handled or
    stored. The original author reports trouble with the
    gas-chromatographic column owing to excessive bleeding and difficulty
    in obtaining good quality glass capillary columns. The amide is
    distinctly polar and tailing occurs during the chromatographic step.

         Work in Australia (Snelson, 1978) has led to the development of a
    method which depends on the reaction of the amino group with Coomassie
    Brilliant Blue G, a dyestuff normally used for dyeing wool and
    polyamide fibres. This forms a stable blue complex which may be
    measured in a spectrophotometer at 595 nm. The procedure involves

    extraction with butanol in the presence of excess alkali using a
    blender. The first extraction gives about 60% recovery and two
    extractions greater than 90%. The butanol extract is recovered by
    centrifuging and after dilution with hexane is washed with sodium
    hydroxide before being partitioned into sulphuric acid. The sulphuric
    acid solution is neutralized and re-extracted with butanol. The
    extract is diluted with hexane and then partitioned into phosphoric
    acid. The phosphoric acid solution is reacted with Coomassie Brilliant
    Blue G and the coloured product determined by measurement at 595 nm.
    Calibration is with a solution of the reaction product of the standard
    and the dyestuff. Reproductable results have been obtained on three
    classed of citrus (oranges, lemons and tangerines) and on cantaloups.
    The outcome of this ongoing study is to be published.


         The following MRLs were reported:

    The Netherlands

         Raw cereals ................... 0.1 mg/kg (at or about the limit
                                         of determination)


         Citrus ........................ 6 mg/kg


         Guazatine is a fungicide developed for the control of cereal seed
    diseases and leaf diseases of cereals including rice blast. It is also
    used against diseases of pineapple, sugar cane and of seed potatoes,
    and for preventing diseases that cause severe post-harvest wastage of

         Technical material, which has been in production since about
    1974, consists of a standardised mixture of the acetates of guazatine
    and related diguanidines, including guanidated 1,8-diaminooctane and
    higher oligomers such as guanidated trioctylenetetramine. 82-84% of
    the amino groups present are converted to guanidine groups. It is not
    possible to isolate the oligomers or to produce the pure guazatine by
    industrial processes but all oligomers have comparable biological
    activity and are considered together as active ingredients.

         Only four residue trials on citrus have been reported, three of
    which were carried out under atypical conditions so that the results
    are of limited value in estimating the level and fate of residues on
    various citrus varieties treated under a range of commercial
    conditions. The residue remains in the peel and only negligible
    quantities are transferred to pulp or juice.

         Analysis of barley, oat, rye and wheat grain from crops grown
    from guazatine-treated seed failed to reveal any guazatine residues
    when analysed by a method with a limit of determination of 0.1 mg/kg.
    Potatoes harvested from plants grown from guazatine-treated seed also
    contained no detectable residues ( 0.05 mg/kg).

         Pineapples, including pulp, skin and leaf, grown from
    guazatine-treated seed pieces and sugar cane, bagasse, molasses and
    (raw sugar from crops grown from guazatine-treated "setts" showed no
    guazatine residues (0.1 mg/kg).

         Radio-tracer studies on the fate of guazatine following its use
    as a seed dressing indicates that none is transferred to the grain of
    the resulting crop. Such amounts as find their way into the growing
    plant appear to be incorporated into plant tissue after metabolism.

         The product was strongly repellent to chickens, pheasants and
    pigeons but there is no information on its fate in poultry or other
    livestock. Some information on the fate in plants indicates extensive
    metabolism. Following application to soil there is rapid degradation
    with the residues being firmly bound to soil organic matter.

         The only residue analytical method so far developed is apparently
    not easy to adapt to local laboratory conditions, National tolerances
    have been established in the Netherlands for raw cereals and in Sweden
    for citrus.


         The following maximum residue limits are recommended.

                   Commodity           Limit, mg/kg

                   Cereals (raw)       0.1*
                   Pineapples          0.1*
                   Potatoes            0.1*
                   Sugar cane          0.1*

    * at or about the limit of determination.

         The following temporary maximum residue limit is recommended.

         Citrus fruits                  5


    Required (by 1980 and before the MRL for citrus can be confirmed)

    1.   Information on the level, distribution and fate of guazatine
    residues when the material is applied to major citrus fruit varieties
    in commercial practice.

    2.   Information on the level and fate of guazatine residues in meat
    and milk following the feeding of citrus pulp containing residues of
    guazatine to cattle.

    3.   An analytical method suitable for regulatory purposes.


    1.   A teratogenicity study with higher dose levels.


    Ahmed, M. Biological and Chemical Research Institute, Rydalmere
    (1978)              NSW Australia. Submitted for publication.
                        Pesticide Science.

    Anonymous Determination of the acute oral toxicity of Panoctine
    (1973a)             E-116335 in rats. Unpublished report from the
                        Central Institute for Nutrition and Food Research
                        Zeist, CIVO-TNO 3x submitted by Keno Gard.

    Anonymous Feeding experiment with Panoctine-treated seed on pigeons
    (1973b)             and pheasants with respect to the grade of
                        repellency. Unpublished report from the Stensoffa
                        Ecologiska-Station, Lund, submitted by Keno Gard.

    Anonymous Soil analysis. Royal Institute of Technology, Stockholm,
    (1978)              Sweden.

    Bodin, S. Distribution of radioactivity in wheat plants treated with
    (1975)              14C and 3H labelled Panoctine. Keno Gard Report

    Bodin, S. Residual analysis of radio-labelled guazatine acetate
    (1978)              in oranges. Keno Gard report dated 78-08-01.

    Casco Gard Panoctine, new broad spectrum fungicide. Technical
    (1976)              Bulletin. Casco Gard AB, Stockholm, Sweden.

    Davis, B., Boorman, G.C. and Mathew, R. Acute pharmacodynamic activity
    (1969)              of EM 379 in cats. Unpublished report from Glaxo
                        Research Ltd. No. 69 PG 1.

    De Groot, A.P. Determination of the intraperitoneal toxicity of
    (1976a)             Panoctine R 42 in rats.  Unpublished report from
                        the Central Institute for Nutrition and Food
                        Research Zeist, No. CIV0-NTO 21-1-76, submitted by
                        Keno Gard.

    De Groot, A.P. Determination of the acute oral toxicity of
    (1976b)             Panoctine 42 in cats. Unpublished report from the
                        Central Institute for Nutrition and Food Research
                        Zeist, submitted by Keno Gard.

    Feron, V.J. and Mullink, J.W.M.A. The effect of guazatine on blood
    (1977)              pressure: a 13-week study in mice. Unpublished
                        report from the Central Institute for Nutrition
                        and Food Research Zeist, No. R 5379, submitted by
                        Keno Gard.

    Hartill, W.F.T., Canter-Visscher, T.W. and Sutton, P.G. An
    (1977)              alternative fungicide to benomyl for the control
                        of green mould in citrus. N.Z. J. Exp. Agric. 5:

    Kemanord, A.B. Residue Analysis of Guazatine in Potatoes from
    (1976a)             Sweden. 1976 Report of Kemanord AB -

    Kemanord, A.B. Research Laboratory - Residue Analysis of cane and
    (1976b)             products from cane. Havali, 1976.

    KenoGard Basic data for determination of tolerance for Panoctine in
    (1978)              citrus. Submission to FAO 78-08-01.

    Kivimäe, A. Feeding experiment with Panoctine-treated grain on
    (1973)              egg-laying hens. Unpublished report of the Poultry
                        Department, The Royal Agricultural College of
                        Sweden, submitted by Keno Gard.

    Kruysse, A. and Immel, H.R. Acute inhalation toxicity study with
    (1976)              Panoctine 42 in rats. Unpublished report from the
                        Central Institute tor Nutrition and Food Research
                        Zeist, No. R 4956, submitted by Keno Gard.

    Leegwater, D.C. Study on the fate of (14C, 3H) Guazatine
    (1975)              preparation in the rat and in sandy loam,
                        Unpublished report from the Central Institute for
                        Nutrition and Food Research Zeist, No. 4823,
                        submitted by Keno Gard.

    Lund Feeding experiment with Panoctine - treated seed on pigeons and
    (1973)              pheasants with respect to the grade of repellency.
                        Report of Stensoffa Ecologiska Station - Sweden.

    Mori, Y. A method for the determination of guazatine residues
    (1975)              in mandarine orange. Report of Dainipon Ink and
                        Chemicals Inc,, Japan.

    Petersen et al., Anal. Biochem., 31: 189 and 204.

    Reuzel, P.G.J., Til, H.P. and Köllen, C.H. Long term (2-year)
    (1976)              toxicity study with Guazatine in beagle dogs.
                        Unpublished report from the Central Institute for
                        Nutrition and Food Research Zeist, No. R 4983,
                        submitted by Keno Gard.

    Reznich, H. and Greenberg, R. Panoctine residues in oranges. Report of
    (1977)              Plant. Protection Institute, Israeli Ministry of
                        Agriculture, July 1977.

    Sinkeldam, E.J. and van der Heijden, C.A. Sub-chronic (90-day)
    (1974)              toxicity study with guazatine in albino rats
                        (final report). Unpublished report from the
                        Central Institute for Nutrition and Food Research
                        Zeist, No. R 4354, submitted by Keno Gard.

    Snelson, J.T. Personal communication to FAO.

    Spanjer, M. Th. and Til, H.P. Determination of the acute toxicity
    (1974a)             (LC50 -96 hours) of Guazatine in carps (Cyprinus
                        carpio). Unpublished report from the Central
                        Institute for Nutrition and Food Research Zeist,
                        No. R 4523, submitted by Keno Gard.

    Spanjer, M.Th. and Til, H.P. Determination of the acute toxicity
    (1974b)             (LC50 - 96 hours) of Guazatine in guppies.
                        Unpublished report from the Central Institute for
                        Nutrition and Food Research Zeist, No. R 4399,
                        submitted by Keno Gard.

    Svensson, S.A. Feeding experiment with fodder treated with
    (1975)              Imazalil plus Panoctine to domestic hens. Report
                        of Institute of Animal Husbandry of the
                        Agricultural College, Uppsala, Sweden.

    Thornberg, O. Residue analysis of panoctine in pineapple from
    (1976)              Hawaii 1976. Report of Kemanord Analyscentrum.

    Thornberg, O. Residue analysis of guazatine in cereals from
    (1977)              Sweden 1974. Kemanord AB Report 1/2/77.

    Thornberg, O. Proposed method for determination of residues of
    (1978)              panoctine in citrus fruit. KemaNord Analyscentrum
                        method 780124.

    Til, H. P. and Feron V.J. Feeding study with guazatine in rats
                        for 13 weeks. Unpublished report from the Central
                        Institute for Nutrition and Food Research Zeist,
                        No. R 48709 submitted by Keno Gard.

    Til, H.P., Köeter, H.B.W.M., Immel, H.R. and van der Heijden,
    (1976a)             C.A. Multigeneration study with guazatine in rats.
                        Unpublished report from the Central Institute for
                        Nutrition and Food Research Zeist, No. R 5078,
                        submitted by Keno Gard.

    Til, H.P. and Hendriksen, C.F.M. Toxicity study with panoctine
    (1976b)             42 (guazatine) in rats for 13 weeks. Unpublished
                        report from the Central Institute for Nutrition
                        and Food Research Zeist, No. R 5062, submitted by
                        Keno Gard.

    Til H.P., Hendriksen, C.F.M. and van der Heijden, C.A.
    (1976c)             Combined chronic toxicity and carcinogenicity
                        study with guazatine in rats (final report).
                        Unpublished report from the central Institute for
                        Nutrition and Food Research Zeist, No. R 4985,
                        submitted by Keno Gard.

    Tugwell, B.L. A system of post-harvest mould control of citrus
    (1977)              fruits in South Australia. Australian Citrus News,
                        August 1977 P. 11.

    van Beek, R. Eye irritation test with panoctine 42 in albino
    (1974)              rabbits. Unpublished report from the Central
                        Institute for Nutrition and Food Research Zeist,
                        No. 4363, submitted by Keno Gard.

    van Beek, R., van Oostrum, E.C.M. and Immel, H.R. Acute dermal
    (1976)              toxicity study with panoctine 42 in albino
                        rabbits. Unpublished report from the Central
                        Insititute for Nutrition and Food Research Zeist,
                        No. R 4921, submitted by Keno Card.

    See Also:
       Toxicological Abbreviations
       Fenthion (ICSC)
       Fenthion (WHO Pesticide Residues Series 1)
       Fenthion (WHO Pesticide Residues Series 5)
       Fenthion (Pesticide residues in food: 1977 evaluations)
       Fenthion (Pesticide residues in food: 1979 evaluations)
       Fenthion (Pesticide residues in food: 1980 evaluations)
       Fenthion (Pesticide residues in food: 1983 evaluations)
       Fenthion (Pesticide residues in food: 1995 evaluations Part II Toxicological & Environmental)
       Fenthion (Pesticide residues in food: 1995 evaluations Part II Toxicological & Environmental)
       Fenthion (Pesticide residues in food: 1997 evaluations Part II Toxicological & Environmental)