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close this bookFAO specifications for plant protection products. Fungicides: Flusilazole (tentative). Herbicides: Chloridazon, Chlorsulfuron (tentative), Diflufenican, Metsulfuron Methyl. Insecticides: Methomyl, Thiodicarb. Plant growth regulators: Ethephon. (1998)
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Thiodicarb aqueous suspension concentrates

FAO Specification 543/SC/S/F (1997)


The material shall consist of a suspension of fine particles of technical thiodicarb, complying with the requirements of FAO specification 543/TC/S/F (1997), in an aqueous phase, together with suitable formulants. After gentle agitation the material shall be homogeneous (Note 1) and suitable for further dilution in water.


2.1 Identity tests (543/SC/M/2, CIPAC H, to be published) (Note 2)

An identity test is required if the identity of the active ingredient is in doubt (e.g. chromatographic retention time under conditions of the method of analysis or IR Spectrum)

2.2 Thiodicarb (543/SC/M/3, CIPAC H, to be published) (Note 2)

The thiodicarb content shall be declared (g/l at 20°C, Note 3) and, when determined, the content obtained shall not differ from that declared by more than the following amounts:

Declared content

Permitted tolerance

up to 5 00 g/l

± 5% of the declared content

above 500 g/l

± 25 g/l


3.1 Manufacturing impurities (Note 2)

Methomyl: Maximum 0.5 % of the thiodicarb content found under 2.2.


4.1 Mass per millilitre at 20°C (MT 3.3, CIPAC F, p. 18) (Note 3)

The range of the mass per millilitre (g/ml) at 20°C shall be declared.

4.2 pH range (MT 75.2, CIPAC F, p. 205)

pH range: 4.0 to 7.0.

4.3 Pourability (MT 148, CIPAC F, p. 348. Note 4)

Maximum “residue”: 5%.

Maximum “rinsed residue”: 0.6%.

4.4 Spontaneity of dispersion (MT 160, CIPAC F, p. 391)

A minimum of 90 % of the content found under 2.2 shall be in suspension after 5 min. in CIPAC Standard Water D at 30°C ± 2°C.

Alternatively, if the buyer required other CIPAC Standard Waters or temperatures to be used, then this shall be specified when ordering.

4.5 Suspensibility (MT 161, CIPAC F, p. 394) (Note 5)

A minimum of 70% of the content found under 2.2 shall be in suspension after 30 min. in CIPAC Standard Water D at 30°C ± 2°C.

Alternatively, if the buyer requires other CIPAC Standard Waters or temperatures to be used, then this shall be specified when ordering.

4.6 Wet sieve test (MT 59.3, CIPAC F, p. 179) (Note 6)

Maximum: 1 % of the product shall be retained on a 75 ìm test sieve.

4.7 Persistent foam (MT 47.2, CIPAC F, p. 152) Maximum: 15 ml after 1 min. (10 g/l dilution).


5.1 Stability at 0°C (MT 39.1, CIPAC F, p. 128)

After storage at 0°C ± 1°C for 7 days, the product shall continue to comply with 4.4, 4.5 and 4.6.

5.2 Stability at 54°C (MT 46.1, CIPAC F, p. 149)

After storage at 54°C ± 2°C for 14 days, the determined average active ingredient content must not be lower than 95% relative to the determined average content found before storage (Note 7) and the product shall continue to comply with 3.1, 4.2, 4.3, 4.4,4.5 and 4.6.


1. Before sampling to verify product quality, inspect the commercial container carefully. On standing, suspension concentrates usually develop a concentration gradient from the top to the bottom of the container. This may even result in the appearance of a clear liquid on the top and/or of sediment on the bottom. Therefore, before sampling, homogenize the product according to the instructions given by the manufacturer or, in the absence of such instructions, by gentle shaking of the commercial container (for example by inverting the closed container several times). Large containers must be opened and stirred adequately. After tins procedure, the container should not contain a sticky layer of non-dispersed product at the bottom. A suitable and simple method of checking for a non-dispersed sticky layer (“cake”) is by probing with a glass rod or similar device adapted to the size and shape of the container. All the physical and chemical tests must be carried out on a laboratory sample taken after the recommended homogenization procedure.

2. Methods available from the Pesticides Information Officer, FAO Plant Production and Protection Division.

3. Unless homogenization is carried out carefully, it is possible for the sample to MT 3.3 are used.

If the buyer requires both g/kg and g/l at 20°C, then in case of dispute, the analytical results shall be calculated as g/kg.

4. This is to ensure that the user can make use of the maximum amount of the ‘ product in the container. Suspension concentrates are fairly viscous products. The test determines the ease with which the formulation pours out of the container and how easily it rinses out.

5. Chemical assay is the only fully reliable method of measuring the mass of active ingredient still in suspension. However, simple methods such as gravimetric and solvent extraction determination may be used on a routine basis provided that these methods have been shown to give equal results to those of the chemical assay method. In case of dispute the chemical method shall be the “Referee method”.

6. This test detects coarse particles (e.g. caused by crystal growth) or agglomerates (crust formation) or extraneous material which could cause blockage of spray nozzles or filters in the spray tank.

7. Analysis of the product before and after storage should be carried out at the same time (i.e. after storage) to reduce the analytical error.