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         It must be noted that the issue of a Data Sheet for a
    particular pesticide does not imply endorsement of the pesticide by
    WHO or FAO for any particular use, or exclude its use for other
    purposes not stated. While the information provided is believed to
    be accurate according to data available at the time when the sheet
    was compiled, neither WHO nor FAO are responsible for any errors or
    omissions, or any consequences therefrom.

    The issue of this document does    Ce document ne constitue pas une
    not constitute formal              publication. Il ne doit faire
    publication. It should not be      l'objet d'aucun compte rendu ou
    reviewed, abstracted or quoted     résumé ni d'aucune citation sans
    without the agreement of the       l'autorisation de l'Organisation
    Food  and Agriculture              des Nations Unies pour
    Organization of the United         l'Alimentation et l'Agriculture
    Nations or of the World Health     ou de l'Organisation Mondiale de
    Organization.                      la Santé.


                               Primary use: Insecticide, acaricide

                               Secondary use: None

                               Chemical group: Organophosphorus compound

                               Date issued: March 1988


    1.1  COMMON NAME

         thiometon (BSI, E-ISO, F-ISO, F-ISO, JMAF), dithiomethon
    (France), M-81 (USSR), exceptions (Federal Republic of Germany,
    Portugal, Turkey).

    1.1.1  Identity

         IUPAC: S-2-ethylthioethyl O,O-dimethyl phosphorodithioate

         CAS: S-[2-(ethylthio)ethyl] O,O-dimethyl phosphorodithioate

         CAS Reg. No.: 640-15-3

         Molecular formula: C6H15O2PS3

         Relative molecular mass: 246.3

         Structural formula:


    1.1.2  Synonyms

         Dithiometon, EkatinR, Ekatin Aerosol, EkatinR, ULV, Ekatin
    WF ULV, Intrathion, Intration, Luxtstelm, M-81.

    1.2  SYNOPSIS

         Thiometon is a systemic organophosphorus insecticide -
    acaricide with residual activity of up to three weeks. It is highly
    toxic to mammals by the oral route. Thiometon is rapidly metabolized
    in both animals and plants to the water-soluble sulfoxide and
    sulfone. Some of the metabolites of thiometon are more potent
    inhibitors of cholinesterases and are more toxic than thiometon


    1.3.1  Physical characteristics

         The pure product is a colourless oil with a characteristic
    odour; b.p. 110°C at 13.3 Pa, d20 1.209, n20 1.5515.
                                   4          4

    1.3.2  Solubility

         Titometon is soluble in water at 200 mg/L (25°C), and in most
    organic solvents, but only slightly soluble in light petroleum.

    1.3.3  Stability

         Low stability in the pure state, but stable in non-polar
    solvents. It is hydrolysed in aqueous solutions, both under alkaline
    or acid conditions.

    1.3.4  Vapour pressure: 23 mPa at 20°C.


    1.4.1  Common formulations

         Emulsifiable concentrates (250 g/L) and ULV (150 g/L). In
    emulsifiable concentrate formulations it is mixed with parathion,
    endosulfan, fenvalerate or quinalphos, and in ULV concentrate with

    1.4.2  Susceptible pests

         Thiometon is effective against sucking insects, mainly aphids,
    and mites on most crops. Others include psyllids, sawflies, jassids
    and thrips.

    1.4.3  Use pattern

         Used as a foliar spray on many crops and ornamentals. Applied
    at a 0.1% concentration rate when the plant is actively growing for
    maximum systemic effect. May also be used as a soil drench.

    1.4.4  Unintended effects

         Considered non-phytotoxic and of low toxicity to bees.


         No recommended usage.


         No recommended usage.



    2.1.1  Absorption route

         Thiometon may be absorbed from the gastro-intestinal tract,
    through the intact skin or by inhalation of spray mist.

    2.1.2  Mode of action

         Thiometon is an organophosphorus insecticide which is not a
    strong cholinesterase inhibitor but when metabolized it converts to
    several potent cholinesterase inhibitors. Absorption is rapid and
    formulations may be more toxic than the pure compound.

    2.1.3  Excretion products

         Rats given 15 mg/kg b.w. of labelled thiometon orally, after 24
    hours excreted 83% of the radioactivity in the urine and 5.5% in the
    faeces, with 4% remaining in the carcass after 96 hours. Maximum
    blood levels were attained after three hours. Primary metabolites
    were O-thiometon sulfoxide, O-thiometon sulfone and O,O-
    dimethylphosphoric acid in proportions of 26, 5 and 52% of the
    urinary excretion, respectively.

    2.1.4  Toxicity, single dose

         Oral LD50:

         Rat                      225 mg/kg b.w. (pure)
         Rat                      190 mg/kg b.w. (technical thiometon)
         Rat                  100-120 mg/kg b.w. (as 25% EC formulation)
         Guinea pig (M)           261 mg/kg b.w.
         Rabbit (M)                95 mg/kg b.w.
         Mouse (M)                 66 mg/kg b.w.
         Mouse (F)                 62 mg/kg b.w.

         Dermal LD50 (four hour exposure):

         Rat (M)               >1 100 mg/kg b.w.

         Intraperitoneal LD50:

         Rat (M)                   45 mg/kg b.w.
         Rat (F)                   47 mg/kg b.w.

         Intravenous LD50:

         Rat (M)                 27.5 mg/kg b.w.
         Rat (M)                 35.5 mg/kg b.w.
         Rabbit                  22.0 mg/kg b.w.

         Inhalation LC50 (one hour):

         Rat (M,F)                >60 mg/L


         Application of 0.5 ml 94.8% pure thiometon for 24 hours with
    occlusion to intact or abraded rabbit skin showed no evidence of
    irritative effects. Instillation of 0.1 ml 94.8% pure thiometon to
    rabbit eyes showed that thiometon had no irritant or corrosive

    2.1.5  Toxicity, repeated doses

         Results of studies in rats given repeated doses of thiometon
    were inconsistent. Formulations may be significantly more toxic than
    the pure compound.

         Oral: In a 12 month study in rats given thiometon from 0 to
    18 mg/kg/day by gastric intubation, a level of > 1 mg/kg/day
    caused a decrease in erythrocyte cholinesterase activity. At > 2
    mg/kg/day an additional decrease in plasma acholinesterase activity
    occurred. A slight reduction in weight gain occurred at 6 mg/kg/day
    which became more significant at the highest dose level. This effect
    was seen only in male rats. All histological findings were normal.

         In another experiment rats given 4 to 7 doses of Intrathion
    (thiometon, supposedly impure) intragastrically at a dose level of
    0.6 LD50 at three day intervals, showed clinical signs of
    poisoning after each dose. Some rats showed flaccid neuro-muscular
    paralysis after 10 to 19 days and on sacrifice showed significant
    decreases in the total phospholipid, sphingomyeline, phosphatidyl
    ethanolamine, phosphatidylserine and total and free cholesterol
    levels in lipid extracts of the spinal cords. Also seen were
    significant increases in phosphoinositides, polyglycerophosphatides,
    lecithin and esterified cholesterol levels.

         In a 13 week study, male rats were given 5, 10, 15 or 20
    mg/kg/day. All animals showed a mild to severe poisoning with all
    animals in dose groups >15 mg/kg/day dying. The survivors
    recovered after 10 weeks whilst still receiving thiometon and
    histological examination failed to reveal abnormal pathology at 13

    2.1.6  Dietary studies

         Short term: In a four week study, groups of rats fed diets
    with thiometon at 0, 0.5, 2, or 5 ppm showed no effects upon plasma
    cholinesterase activity, growth and behaviour. A slight inhibitory
    effect on erythrocyte and brain cholinesterase activity was seen at
    the highest dose level of 5 ppm. No observed effect level (NOEL) was
    found to be 2 ppm.

         In a 90 day study, groups of rats fed thiometon at 0, 5, 15 or
    45 ppm showed mortality in the highest dose group after the fourth
    week. Plasma and erythrocyte cholinesterase activity was depressed
    in rats fed on a diet containing > 15 ppm of thiometon and
    erythrocyte cholinesterase was only slightly inhibited in rats from
    the 5 ppm group. No histopathological changes were found.

         In a 90 day study, beagle dogs fed thiometon at 0, 10, 20 or 40
    ppm (equivalent to 0, 0.35, 0.65 and 1.40 mg/kg/day respectively)
    showed no effects on the amount of food consumed, growth,
    histopathology or behaviour. In the highest dose group, depression
    of plasma cholinesterase activity occurred towards the end of the
    study. Erythrocyte cholinesterase activity was affected in rats fed
    on a diet containing thiometon over 20 ppm. Brain cholinesterase
    activity remained normal in all dose groups. NOEL was 10 ppm.

         Long term: A two year rat feeding study was initiated at
    doses of 0, 0.2, 1, 2 or 20 ppm. After six weeks the concentration
    was increased to 0, 1, 2.5, 6.25 or 300 ppm respectively. Shortly
    after increasing the dose levels, the rats fed on a diet containing
    300 ppm lost weight and showed signs of acute poisoning and some
    deaths occurred. In the survivors the body weight remained low
    during the rest of the study due to decreased food and water
    consumption. In females of this group, haemoglobin, mean corpuscular
    volume and mean corpuscular haemoglobin levels were decreased as
    well as blood glucose, protein and cholesterol. Plasma, erythrocyte,
    and brain cholinesterases were strongly inhibited in both sexes at
    this dose level. Lower values for plasma and erythrocyte
    cholinesterase activities were occasionally observed in rats fed on
    a diet containing 6.25 ppm thiometon. In rats on a diet of 2.5 ppm
    erythrocyte cholinesterase activity was marginally reduced (<20%).
    Erythrocytes, leukocytes as well as amorphous uric acid crystals
    occurred in the urine at the highest dose level during the last half
    of the study. The urine also had a higher specific gravity. Relative
    organ weights were increased in the highest dose group save for the
    spleen which had a decrease in relative weight, and the liver which
    had a decreased relative weight in males only. No specific lesions
    were induced at any dose level. NOEL was 2.5 ppm.

         Dietary administration of 6, 12 or 48 ppm thiometon to dogs for
    two years resulted in decreased cholinesterase activity in brain,
    plasma and erythrocytes at 48 ppm and in erythrocytes and plasma.

    (marginal decrease) at 12 ppm. No changes in mortality or in
    histopathological, ophthalmological or behavioural parameters, nor
    dose-related changes in urinalysis, haematological or clinical
    chemistry parameters were observed. NOEL was 6 ppm.

    2.1.7  Supplementary studies

         Carcinogenicity: No tumours were found in the rat dietary
    studies described above, that could be related to administration of

         Mutagenicity: Thiometon was found to be mutagenic in
    metabolically non-activated systems in several strains each of
     Salmonella thyphimurium (his auxotrophs) G46, TA1530, TA1535, and
     Escherichia coli causing base substitutions. Thiometon did not
    demonstrate any mutagenic effect in two mouse micronucleus tests nor
    in an Ames Salmonella/microsome plate test.

         Teratogenicity: Female rabbits treated with thiometon at 1 or
    5 mg/kg/day from the sixth to the eighteenth day of pregnancy showed
    no evidence of teratogenic or embryotoxic effects.

         Reproduction: A marginal effect on reproduction in rats was
    reported following dietary administration of 6.25 ppm for three
    generations. No adverse effects were noted at 1 or 2.5 ppm but at
    6.25 ppm a lower lactation index, reduced viability, reduced pup
    weight and/or an increase in stillborn births were observed in some
    or all of the generations. There was no effect on gestation indices
    and no adverse histopathological or teratogenic effects.

         Neurotoxicity: Flaccid neuromuscular paralysis was observed
    in rats 10-19 days after oral administration of 4-7 doses of
    Intrathion, each 0.6 of the LD50, administered at three day
    intervals. These events were paralleled by biochemical changes in
    the spinal cord (Section 2.1.5). Examination of the spinal cord by
    light and electron microscopy revealed demyelination and nerve cell
    degeneration. In a special study in chickens, given thiometon
    intramuscularly at a dose of 35 mg/kg, and protected with atropine
    and pralidoxime, no signs of neurotoxicity were seen during an
    observation period of 29 days.


    2.2.1  Absorption route

         Thiometon may be absorbed from the gastrointestinal tract,
    through intact skin or from the lungs.

    2.2.2  Dangerous doses

         No published information available.

    2.2.3  Observations on occupationally exposed workers

         Twelve female agricultural workers exposed to Intrathion showed
    changes in catalase, cytochrome oxidase and ceruloplasmin levels.
    Some of these changes persisted for six months post-exposure. These
    parameters are generally not examined for in cases of
    organophosphorus poisoning and their interpretation is difficult.
    Reduced blood cholinesterase activity has been reported in workers
    during thiometon manufacture but there were no signs of illness.

    2.2.4  Observations on exposure of the general public

         No published information available.

    2.2.5  Observations on volunteers

         No published information available.

    2.2.6  Reported mishaps

         A 63 year old female ingested the equivalent to a full glass of
    a 50% thiometon (Ekatin 50%) formulation. The victim experienced
    painful abdominal cramps, diarrhoea, a weak and rapid pulse and cold
    extremities. The victim vomited many times and was generally sleepy,
    weak with extensive fasciculations visible on the trunk and limbs.
    Tendon reflexes were elicitable and quadriceps muscle reflexes
    lively. Plantar was of the flexor type. Neuromuscular synapse
    insufficiency tests were normal but the victim had low blood
    acetylcholinesterase activity. The dose was apparently non-fatal.


    2.3.1  Fish


         Rainbow trout                  8.0 mg/L (96 hr)
         Carp                          13.2 mg/L (96 hr)

    2.3.2  Birds

         No published information available.

    2.3.3  Other species

         Thiometon was observed to be slightly toxic to Daphnia magna,
    green algae, earthworms and bees.



         (For definition of categories see the Introduction to Data

         Liquid formulations of 600 g/L and over, Category 2
         Other liquid formulations, Category 3
         Solid formulations of 250 g/kg and over, Category 3
         Other solid formulations, Category 4


         All formulations: Thiometon should be transported and stored
    in clearly labelled impermeable containers, away from containers of
    food and drink. Storage should be under lock and key, secure from
    access by children and other unauthorized persons.

    3.3  HANDLING

         All formulations: Full protective clothing (see section 4.3)
    should be used by those handling the compound. Adequate washing
    facilities should be available at all times during the handling and
    should be close to site of handling. Eating, drinking and smoking
    should be prohibited during handling and before washing after


         All formulations: Containers must be firstly decontaminated
    and then crushed and buried below topsoil. Care must be taken to
    avoid subsequent contamination of water sources. Decontamination of
    containers in order to use them for other purposes should not be


         All formulations: Pre-employment medical examination of
    workers is necessary. Workers suffering from active hepatic or renal
    disease should be excluded from contact with thiometon. A pre-
    employment and periodic blood cholinesterase test for workers is
    desirable. Special account should be taken of the workers' mental
    ability to comprehend and follow instructions. Training of workers
    in techniques to avoid contact is essential.


         All formulations: Pilot and loaders should have special
    training in application methods and in recognition of the early

    symptoms of poisoning. Protective clothing (Section 4.3) must be
    worn. Flagmen, if used, should wear overalls, an impermeable broad
    brimmed hat, impermeable boots and gloves, and a respirator, and be
    located well away from the dropping zone.

    3.7  LABELLING

         Formulations in Category 2, Minimum Cautionary Statement

                             "DANGER - POISON"
                      (SKULL AND CROSS-BONES INSIGNIA)

         Thiometon is a highly toxic organophosphorus compound which
    inhibits cholinesterases. Contact with the skin, inhalation of dust
    or spray, or swallowing may be fatal. Wear protective gloves, clean
    protective clothing, and a respirator of the organic-vapour type
    when handling this material. Wash immediately after handling. Ensure
    that containers are stored under lock and key. Empty containers must
    be decontaminated and disposed of in such a way so as to prevent all
    possibility of accidental contact with them. Keep the material out
    of reach of children and well away from foodstuffs, animal feed and
    their containers. In case of contact, immediately remove
    contaminated clothing and wash the skin thoroughly with soap and
    water; for eyes, flush with water for 15 minutes.

         If poisoning occurs, call a physician. Atropine and pralidoxime
    are accepted antidotes, repeated doses may be necessary. Artificial
    respiration also may be needed.

         Formulations in Categories 3 and 4, Minimum Cautionary

                             "WARNING - POISON"
                      (SKULL AND CROSS-BONES INSIGNIA)

                      (for test of statement see above).


     Maximum residue levels

         Maximum residue levels have been recommended by the Joint
    FAO/WHO Joint Meeting on Pesticide Residues. Acceptable daily intake
    for man has been estimated to be 0-0.003 mg/kg body weight.



    4.1.1  General

         Thiometon, an organophosphorus pesticide is highly toxic to
    mammals. Besides the oral route, it may be absorbed through the
    intact skin and by inhalation of dust or spray mist. Repeated
    exposure may have a cumulative inhibitory effect on cholinesterases.
    Most formulations should be handled by trained personnel wearing
    protective clothing.

    4.1.2  Manufacture and formulations

         For T.L.V. no information available.

         Closed systems and forced ventilation are required to minimize
    the exposure of workers to the chemical.

    4.1.3  Mixers and applicators

         When opening the container and when mixing, protective
    impermeable boots, clean overalls, gloves and a respirator of the
    organic-vapour type should be worn. Mixing, if not mechanical,
    should always be carried out with a paddle of appropriate length.
    When spraying tall crops or during aerial application, a respirator
    should be worn, as well as an impermeable hat, protective clothing,
    boots and gloves. The applicator should avoid working in spray mist
    and avoid contact with the mouth.

         Particular care is needed when equipment is being washed after
    use. All protective clothing should be washed immediately after use,
    including the insides of gloves. Splashes must be washed immediately
    from the skin, or eyes, with large quantities of water. Before
    eating, drinking or smoking, hands and exposed skin, should be

    4.1.4  Other associated workers (including flagmen in aerial

         Persons exposed to thiometon and associated with its
    application should wear protective clothing and observe the
    precautions described above in 4.1.3 under "Mixers and applicators".

    4.1.5  Other populations likely to be affected

         With good agricultural practices, subject to 4.2 below, other
    persons should not be exposed to hazardous amounts of thiometon.


         Unprotected persons should be kept out of tall crops for four
    days and out of other crops for 24 hours.


         Residues in containers should be emptied in a diluted form into
    a deep pit, and empty containers should be burned or buried, taking
    care to avoid contamination of water sources. Re-use of empty
    containers is prohibited (section 3.4). Spillage of thiometon and
    its formulations should be removed by washing with 5% sodium
    hydroxide solution and then rinsing with large quantities of water.


    4.4.1  Early symptoms of poisoning

         Early symptoms of poisoning may include excessive sweating,
    headache, weakness, giddiness, nausea, vomiting, hypersalivation,
    stomach pains, blurred vision, slurred speech and muscle twitching.
    Later there may be convulsions and coma in cases of severe

    4.4.2  Treatment before person is seen by a physician, if these
           symptoms appear following exposure

         The person should stop work immediately, remove contaminated
    clothing and wash the affected skin with water and soap, and flush
    the area with large quantities of water. If swallowed, and if the
    person is conscious, vomiting should be induced. In the event of
    collapse, artificial resuscitation should be given, bearing in mind
    that if mouth-to-mouth resuscitation is used, vomit may contain
    dangerous amounts of thiometon.



    5.1.1  General information

         Thiometon is an organophosphorus pesticide, highly toxic to
    mammals. It is readily absorbed from the gastrointestinal tract,
    through the intact skin, and by inhalation of dust or spray mist. It
    is converted  in vivo to the oxygen analogues of thiometon which
    are more potent inhibitors of cholinesterases.

    5.1.2  Symptoms and signs

         Initial symptoms and signs of poisoning may include excessive
    sweating, headache, weakness, giddiness, nausea, hypersalivation,
    vomiting, stomach pains, blurred vision, slurred speech and muscle
    twitching. More advanced signs of poisoning may be convulsions coma,
    loss of reflexes and loss of sphincter control.

    5.1.3  Laboratory

         The most important finding is reduction of activity of blood
    cholinesterases. Urinary levels of organic phosphorus containing
    metabolites may also be used as a measure of exposure. Neither
    method is specific for thiometon.

    5.1.4  Treatment

         If the pesticide has been ingested, unless the patient is
    vomiting, rapid gastric lavage should be performed using 5% sodium
    bicarbonate. Care must be taken to avoid pulmonary complications
    from solvents following ingestion of emulsifiable concentrate
    formulations. For skin contact, the skin should be washed with water
    and soap. If the compound has entered the eyes, they should be
    washed with copious volumes of water or isotonic saline. Care must
    be taken by the victims attendants to avoid their own intoxication
    from contaminated clothing, skin or body fluids.

         Persons without signs of respiratory insufficiency but with
    manifest peripheral symptoms should be treated with 2-4 mg of
    atropine sulfate by intravenous injection followed by 250 mg
    toxogonin (adult dose) or 1 000 mg pralidoxime chloride (adult
    dose), by slow intravenous injection. The additional therapy with
    pralidoxime (or toxogonin) is likely to be successful if
    administered within 24 hours of the onset of intoxication. However,
    it may continue to be effective in the following days and treatment
    should continue until no further benefit to clinical or biochemical
    parameters is observed. More atropine may be given as needed.
    Persons with severe intoxication, with respiratory difficulties,
    cyanosis, convulsions or unconsciousness should immediately be given
    oxygen and atropine sulfate followed by pralidoxime chloride. In
    such severe cases 4-6 mg of atropine sulfate should be given
    initially followed by repeated doses of 2 mg at 5-10 minute
    intervals. Diazepam may be given to control convulsions. The
    patient's condition should be carefully observed as a guide to
    further administration of atropine. Symptoms will reappear if tissue
    concentrations of thiometon or its metabolites remain high when the
    effect of atropine wears off. Rales in the lung bases, myosis,
    nausea, bradycardia, salivation or convulsions indicate inadequate
    atropinization. Overdosage with atropine (pulse rate over 140, dry
    mouth, flushed face) is rarely serious, but underdosage may be
    fatal. The airways should be kept free and artificial resuscitation

    should be applied if required, preferably by mechanical means. If
    necessary intubation should be performed. Application of morphine,
    aminophylline, phenothiazines, and reserpine is contraindicated. The
    patient should not be allowed to return to work until blood
    cholinesterase activity is over 80% of pre-exposure levels.

    5.1.5  Prognosis

         If the acute toxic episode is survived and if needed adequate
    artificial resuscitation has been given, the chances of complete
    recovery are good. However, in very severe cases, particularly if
    artificial resuscitation has been inadequate, prolonged anoxia may
    give rise to permanent brain damage.

    5.1.6  References of previously reported cases

         No published information available, other than case cited in
    section 2.2.6.


    Test                Normal level*  Action level*  Symptomatic level*

    Plasma                  100%            50%       variable

    Whole blood or          100%            70%       usually 40%


    5.3.1  Detection and assay of compound

         Urinary metabolites may also be determined in order to give an
    indication of exposure. Thin-layer, gas and liquid chromatography
    methods have been used to analyze thiometon in technical products
    and in its formulations. Analysis of residues in plant and animal
    tissues have been described by gas chromatography and flame
    photometry methods.

         Abbot, D.C., Crisp, S.S., Tarrant, V.R., Tatton, J. O'G.
              (1970), Pestic. Sci 1, 10-13.

         Wisson, M., van Hoek, C., Sauer, H.H. (1976), Anal. Methods
              Pestic. Plant Growth Regul., 8, 239-244.


    * Expressed as percentage of pre-exposure activity.

    5.3.2  Other tests in case of poisoning

         Activities of cholinesterases in the blood, provide the most
    useful aid for diagnosis of poisoning, but are not specific for
    thiometon intoxication.


    1.   FAO Plant Production and Protection Paper, 20 sup. (1980),
              Pesticide Residues in Food: 1979 Evaluations, pp. 503-512,
              FAO, Rome

    2.   Farm Chemicals Handbook, (1984), Meister Publishing Co.,
              Willoughby, Ohio 44094, USA

    3.   Hartley, D., Kidd, H., (1983), The Agrochemicals Handbook,
              Royal Society of Chemistry. Unwin Bros. Ltd., Surrey, U.K.

    4.   Hayes, W.J. (1982), Pesticides Studied in Man. Williams and
              Wilkins. Baltimore, USA, pp 377-379.

    5.   Jusic, A., Milic, S., (1978), Neuromuscular synapse testing in
              two cases of suicidal organophosphorus pesticide
              poisoning. Arch. Environ. Health, 33, 240-243.

    6.   Klotzche, C., (1964), Zur toxikologischen Prüfung neuer
              insecticider Phosphorsäureester, Int. Archiv.
              Gewerbepathologie Gewerbehygiene, 21, 92-106

    7.   Thomson, W.T. (1982), Agricultural Chemicals, Book 1.
              Insecticides, 1982-1983 Revision. Thomson Publications
              California 93791, USA.

    8.   Worthing, C.R. (ed) (1987). The Pesticide Manual. A World
              Compendium. 8th Edition. British Crop Protection Council,

See Also:
        Thiometon (PIM 165)