Use of grain protectant insecticides in developing countries

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M. Kern

GTZ Pesticide Residue Project
P.O. Box 4001
D-6100 Darmstadt
Germany

During the late 1960s and early 1970s it became apparent that pesticide residues in agricultural produce were becoming a growing problem in developing countries. This was first recognised in industrialized countries where pesticide residue controls were enforced. As commodities imported from the tropics were also analysed and found to contain residues above the permitted national tolerance levels, many shipments were rejected.

This paper summarises some of the results from investigations on the degradation of insecticide deposits in stored grain, illustrating the main factors affecting residue formation in these commodities.

The climatic conditions surrounding stored grain are much more uniform than those to which field crops are exposed. For example, temperature and moisture content of stored grain are relatively stable, and stored grain is sheltered from wind, rain, and light Desmarchelier (1978) showed that the loss of fenitrothion from postharvest application to wheat, oats, paddy rice, and sorghum followed a second-order rate process. At fixed temperatures, the rate of loss is proportional to both the amount of fenitrothion applied and the grain water activity.

Similar results have been obtained with a wide range of other grain protectant insecticides. These findings agree with data obtained by extensive monitoring of field application of grain protectant insecticides. The rate at which insecticides break down on grain is independent of grain type and follows a first order reaction with respect to water activity (FAO 1982).

Thus, under conditions of constant temperature and grain water activity, it is possible to make a direct comparison of the half lives (the time required for an insecticide to degrade to half the original applied dose) of different insecticides (Table 1). This makes it possible to predict the fate of insecticides during storage.

Loss of insecticide can be predicted from the mean grain temperature and its water activity. So, in practice, application rates can be selected to ensure that grain will be protected from insect attack over the full storage period - and ensure that residues at the end of this period will not exceed the internationally accepted limits.

After grain has been treated the insecticide may move from its covering (the husk in the case of paddy) or outer surface (the seed coat or bran layers), into its internal tissues (the germ and endosperm). The extent of movement ranges from complete retention at the surface of the grain to near equilibrium throughout the whole grain. However, most insecticides used as grain protectants do not move, to any great extent, into individual grains.

Table 1 Half - lives (in weeks) of grain protectant insecticides at 50% relative humudity, and 30° and 36°C

a FAO Plant Production and Protection
Paper (1982)
b Wohlgemuth et al. (1987)
- = no information available

When grains are finally processed for human consumption (by removal of husk, bran, and germ during milling and by exposure to high temperatures during cooking) most residues are removed or destroyed. In the case of wheat and polished rice much of the residue is removed along with the bran and germ during milling (73X in the case of pirimiphos-methyl and 92X for fenitrothion). Similarly, when wheat flour is converted into wholemeal bread, losses of insecticide residues range from 46% in the case of phenothrin to 100% for bioresmethrin and methacriphos (FAO 1982).

Unfortunately, physical, mechanical, and operational difficulties make it impossible to apply grain protectants uniformly over grain. Grain segregation resulting from movement, blending, and transportation further increases the likelihood that any samples taken from discrete sections of a bulk of insecticide-treated grain will yield varying residue levels. FAO makes allowance for such variations when residue limits for grain are set. Usually a factor of about two is regarded as appropriate.

Therefore, even under extreme climatic conditions, grain protectants can be used safely, because their behaviour and the residues they form are predictable and can be controlled.

The problem of postharvest crop losses has arisen in developing countries largely because they have been disregarded and underestimated. There is also a lack of know-how for developing potential storage protection measures. GTZ thus focuses its aid programmes in this field on the following topics.

To overcome the knowledge deficit, priority is given to training and advising agricultural extension workers, plant protection technicians, and officials from government and non-government organisations in all aspects of loss-minimising storage, adequate protection measures, and safe and efficient use of pesticides.

It is stressed that good storage practice combined with a high standard of hygiene are essential for effective application of grain protectant insecticides. Similarly, emphasis is placed on the requirement to apply insecticides in accordance with good agricultural practice. This means that staff using insecticides must be:

• well trained;
• able to read and understand the information on labels, especially the hazard and first aid messages;
• understand the specific requirements for applying individual insecticides; and
• understand the 'withholding period' concept.

Also, precaution has to be taken that no seeds dressed with pesticides are redistributed for consumption, which can lead to serious poisoning.

When pesticides are used, the quality of the product has to be monitored continuously. This is usually done by the respective national authorities. It is important to ensure that formulations and labels are accurate and in accordance with international standards. Particularly in hot climates, certain active ingredients can degrade very rapidly if they are stored improperly. There might also be incorrect labelling of the concentration of active ingredient or even indication of the wrong active ingredient.

Because local pesticide registration schemes in developing countries are often not sufficiently comprehensive, GTZ promotes implementation of the international 'Code of Conduct' through organisation of proper control systems based on legislation and pesticide registration. These involve biological efficacy tests, monitoring of pesticide residues, formulation control, and introduction and regulation of appropriate pesticide packaging and labelling.

References

Desmarchelier, J.M. (1978) Loss of fenitrothion on grains in storage. Pesticide Science, 9: 33-38.

FAO (1982) Pesticide residues in food: 1981 evaluations. Plant production and protection paper No. 42. FAO, Rome.

Wohlgemuth, R. Harnisch, R., Thiel, R., Bucholz, H., and Laborius, A. (1987) Comparing tests on the control and longterm action of insecticides against stored product pests under tropical climate conditions. GTZ PostHarvest Project, Pickhüben 4, D-2000 Hamburg, Federal Republic of Germany.

Pesticide legislation and regulations

J.G. Thiessen

GASGA Joint Secretariat
SPV - Mission de Coopération
BP 7309
34083 Montpellier Cedex 2
France

The harmonisation of legislation and regulations on pesticides is an objective found at various levels:

• FAO international code and its guidelines for application;
• multilateral or bilateral cooperation projects;
• recommendations by donors, advisers, and industry; and
• the preoccupations of various regional organisations, the OAU's Inter-African Phytosanitary Council (IPC), the EEC, etc.

The drafting of standard laws and regulations for countries in a continent such as Africa, with extremely diverse technical, economic, social, and political features, is impossible.

I shall describe here the technical points to be examined in laws and regulations in order to achieve a certain degree of harmonisation. The concepts and principles proposed concern the drawing up of a law on 'Pesticides' and its edict of application.

With regard to the practical aspects, I should like to stress two recommendations drawn up for francophone Africa at the seminar held in Yaounde in November 1987 (organised by France and the OAU's IPC, with assistance from the EEC). The recommendations concern:

• the registration file; and
• the labelling scheme.

1 The legal basis for 'registration and control of pesticides': technical aspects

The basic law drawn up by the legislature should specify the general line of conduct to be followed with respect to pesticides. It is followed by an edict of application. The two documents make it possible for the executive (the ministries concerned) to promulgate the regulations, decrees, circulars, memoranda, etc. required for their practical application.

1.1 Contents of the bill

The text can be drawn up using four headings:

1.1.1 Generalities

These cover

• The subject of law:

'the putting into practice of the national policy on pesticides and particularly concerning the supervision of imports, sales, packaging, labelling, use, storage and disposal of out of date products, and manufacture, repackaging and transport.'

Products destined for export only and which have been prepared and packaged in conformity with the specifications and instructions of the purchaser do not fall within the scope of this legislation.

• Definition of the key words used in the legislation and regulations:

pesticides, plants, plant products, sales, harmful organisms, authorisation of experimentation, provisional sales authorisation, approval or registration, etc.

1.1.2 Management of pesticides

(Principles must be laid down by the law)

• Any unauthorized, non-approved or noncertified pesticide is forbidden.
• Setting up of a body (generally a committee) for approval and registration and which will advise the minister concerned.
• Approval or registration procedure and determination of the possible stages:
• - refusal or postponement, authorization of experimentation;
• - provisional sales authorisation, approval or registration;
• - modification of prior authorisation; and
• - appeal procedure, with the setting of time limits.
• Consequences of chemical, biological or physical modifications or any change in use necessitating re-examination by the Committee,
• Regulations for various points: packaging, labelling, utilisation, experimentation, transport, storage and disposal of pesticides. It is planned that these would be covered by regulations (generally by decree),
• Advertising either forbidden for unauthorized products, or restricted to information contained in the authorisation or approval-registration and in conformity with the laws and regulations in force,
• Fees in payment for examination by the Committee and the attribution of these fees to the ministry concerned; the sum will be laid down by decree,
• Exceptions to approval provisions for research and experimentation requirements,
• Awarding of a licence to manufacturers, formulators, repackers and possibly approval of distributors,
• Register of pesticide management to be kept by the beneficiary of authorisations or approvals and which will enable subsequent verification,
• Diffusion of the conditions and methods of use of pesticides by the ministry entrusted with control
• Professional secrecy obligatory for persons with access to the files submitted to the Committee.

1.1.3 Establishment of offences, penalties

The following points are defined under this heading:

• the personnel entrusted with seeking and recording offences against the law and edicts of application,
• the conditions under which these personnel can exercise their task of verification, and giving them the possibility of:
• - confiscating products which are not in accordance with the law,
• - taking samples for verification purposes,
• - examining all licences, approval documents and registers,
• the sum and nature of the penalties to be applied in case of infringement of the law or the regulations,
• the possibility of settlement,
• the consequences of repetition of the offence.

1.1.4 General provisions

These will make it possible:

• to specify that statutory measures will be taken by the ministry concerned for application of the law,
• to repeal all previous conflicting provisions,
• to indicate that the- law will be published officially.

1.2 Edict of application of the law

This is the first stage in the application of the law. The text defines the responsibilities and missions of each of the partners of the state concerned by the law.

Part I: The Plant Protection Service

The articles under this heading will:

• 1. enable the Plant Protection Service (or similar), and other services which may be concerned, to be entrusted with the control of pesticides, and
• 2. ensure that the Plant Protection Service has competent technical staff, land, laboratories and other installations for carrying out its job.

This provision will make budget negotiations easier.

Part II: The Pesticides Committee

The heading will cover, in conformity with the law, the missions of the committee assisting the Minister, generally carrying out the following tasks:

1. proposal of principles and general guidelines for pesticide regulations,

2. examination of risks of toxicity for man, animals and the environment,

3. perhaps drafting of a list of products whose use in agriculture is forbidden or limited in the light of the risks in point 2,

4. proposal to the Minister concerned of all measures likely to contribute to the standardisation, definition and drawing up of the conditions and methods of use of the pesticides concerned by the law with respect to their biological effectiveness and their disadvantages of all kinds,

5. definition of methods of monitoring the composition, quality and evaluation of the products submitted for authorisation or approval,

6. examination of requests for authorisation and approval/registration for further action,

7. keeping of a public register of authorisations and approvals,

8. giving an opinion on requests for licences or approval planned by the law,

9. requesting, if necessary, expert appraisals by laboratories approved by the administration,

10. giving an opinion on all questions on pesticides submitted by the ministers concerned and drawing up all recommendations within its scope concerning the products.

An article specifies that the composition of the Committee is fixed by interministerial order and that the committee may call upon outside experts.

Part III: Approval/Registration procedure

This part describes the practical procedure for approval and registration:

• requests are forwarded to the committee,
• requests are presented in a prescribed manner:
• - a specific form,
• - summary of toxicological file and packaging specification,
• - effectiveness file,
• - specimen label
• - descriptive note on methods of analysis for monitoring the active ingredient,

(The contents of the files are laid down by interministerial order.)

• pesticide samples are to be provided to enable study of their physical, chemical and biological properties,
• the committee will examine the file and issue:

- an unfavourable opinion, or
- notification of postponement for complementary studies and information, or
- authorisation of experimentation or provisional sales authorisation or approval/registration. Notification may be accompanied by specific conditions.

• duration of the validity of authorisations and approval/registration is laid down in the edict.

The following durations are generally recommended for Africa:

• authorisation of experimentation: 1 year, renewable,
• provisional sales authorisation: 4 years, renewable for 2 years,
• approval/registration: 10 years, renewable possibly once for a further 10-year period.

Part IV: Obligations

These concern the beneficiary of the authorisations and of approval/registration (the industry):

For authorisation of experimentation:

1. program of trials with supervision and control by the authorities,

2. the forbidding of all advertising,

3. labelling in conformity with the standard type laid down by order of the ministry concerned,

4. submission of a note for medical use on treatments in case of poisoning,

5. forbidding the use of the products harvested for human or animal consumption without permission.

For provisional sales authorisation and approval/ registration:

1. an undertaking to put on the market under the specified trade name only the substance defined by:

• its trade name,
• the name of the holder of the trade name,
• the number of the authorisation or approval/registration issued by the Committee,
• the composition of the product, with specification of

- authorised use, doses and methods of application,
- the precautions to be taken by users and the contraindications mentioned in the decision;

2. conformity labelling with the model laid down by the edict.

• The procedure for removal from the market must be planned for products which have been withdrawn or for which renewal of authorisation or approval/ registration has been refused; this procedure depends on the reasons for such withdrawal or refusal.

(Removal is generally carried out immediately in case of problem of public or veterinary health, of the environment or phytotoxicity; products are generally removed after two years if the reasons are different from those above.)

Part V: Establishment of offences, penalties

This lays down in particular that

• the persons entrusted with control should be issued with a professional identity card,
• offences will be the subject of reports,
• a receipt will be given for samples taken,
• the offences concerning the provisions of the edict will be punished as provided for by the law.

Part Vl: General provisions

It is laid down that orders may be issued as required in order to apply the edict and that the edict will be published officially.

2 Measures for practical application

These consist of a set of legal standards which complement the Law and the Edict putting it into application and enable the administration to lay down the technical rules required for approval/registration and for the control of pesticides.

The measures comprise orders, circulars, memoranda, models for forms and registers, etc.

Two points are examined more particularly here as they seem to us to be fundamental for African countries which wish to set up legislation and regulations on pesticides.

The two points are taken from the recommendations drawn up by participants a the seminar on Control and Approval of Pesticides organised by France and the

OAU's Inter-African Phytosanitary Council (IPC). The recommendations concern:

• the establishing of a registration file for francophone Africa,
• labelling, packaging and technical sheets for phytosanitary products.

The texts of each of these recommendations, drawn up by our African colleagues in conformity with the corresponding FAO guidelines, are provided as annexes.

2.1 Registration file

The aim of this recommendation is to provide countries with full, accurate information on the 12 points mentioned without obliging the industry to provide the full studies carried out, which are generally extremely voluminous.

The complete studies must of course be available on request as soon as special interest in a specific point emerges.

These data will be completed by a biological effectiveness file on the product. No standard plan has been designed for this second file.

2.2 Labelling, packaging and the technical card

A desire for harmonisation guided the participants at the seminar during the drawing up of this recommendation, which has resulted in particular in the proposing of a standard label for francophone Africa.

Annex 1 Workshop 'control and registration of pesticides in french speaking Africa' Yalounde, November 1987

3RD RECOMMENDATION

INTRODUCTION OF A REGISTRATION DOSSIER IN AFRICAN COUNTRIES

The registration dossier should be composed of two separate dossiers:

- the first dossier is the actual registration dossier and should include all information on the identification and the physico chemical properties of the formulated product and the active ingredient(s), the toxicology, the effects on the environment, on wildlife and flora, the residues, as well as all aspects relating to the safe use of the product

Since the study reports are very voluminous, we propose that they are not submitted in their entirety, but rather in the form of summaries, which will facilitate their understanding.

The full studies should however be made available on request, in case particular interest on a certain aspect would arise.

This registration dossier, in French and English in the case of bilingual countries, would be in the form of a questionnaire containing the main information on the formulated product and the active ingredient(s). The information on each point would be brief and the completed questionnaire would provide a good general appreciation of the product

A certain number of basic registration documents will be attached as enclosures. Summaries of the main studies would also be included.

- the second dossier includes everything related to the biological effect of the product efficacy, phytotoxicity, etc., and includes results of trials carried out locally and/or in countries with similar climatic and agronomic conditions.

The registration dossier is to be completed with a 'Registration Request' drawn up on a simple form covering the following items:

- Registration number and date
- Name and address of the petitioner
- Name and address of the formulator
- Name and address of the trade mark owner
- Trade name
- Uses (target pests, methods of application, dosage rates, contraindications).

Registration Dossier

1. Information on the physico-chemical properties of the formulated product

1.1 Trade name

1.2 Name of the product manufacturer

1.3 Type of formulation

1.4 Active ingredient(s) content (composition, cf. enclosure)

1.5 Analytical method and reference (details, cf. enclosure)

1.6 Physico-chemical characteristics depending on the type of formulation: appearance of the product, density (liquid products), bulk density (solid products), wettability (wettable powders), suspensibility (wettable powders and suspension concentrates), fineness of the particles (wettable powders, suspension concentrates, granules), emulsion stability (emulsifiable concentrates), viscosity (ULV formulations), flash point, pH in a 1% dilution (products to be diluted in water)

1.7 Storage conditions and shelf life

2. Information on the identity and the physico-chemical properties of the pure active ingredient(s)

2.1 Common
2.2 Chemical designation
2.3 Structural formula
2.4 Empirical formula
2.5 Molecular weight
2.6 Appearance
2.7 Density at 20°C
2.8 Melting point/decomposition point/boiling point
2.9 Vapour pressure
2.10 Volatility
2.11 Hydrolysis
2.12 Solubility in water
2.13 Solubility in organic solvents
2.14 Partition coefficient between water and n-octanol
2.15 Absorption spectra (W. IR etc.)
2.16 Photolysis

3. Physico-chemical information on the technical active ingredient(s)

3.1 Appearance
3.2 Odour
3.3 Density
3.4 Minimal purity
3.5 Maximal content of by-products
3.6 Analytical method: (details, cf. enclosure)

4. Toxicity of the formulated product

4.1 Acute oral LD50 in the rat
4.2 Acute dermal LD50 in the rat
4.3 Acute inhalation LD50 in the rat
4.4 Skin irritation, rabbit
4.5 Eye irritation, rabbit
4.6 Toxicological classification according to FAO/WHO

5. Toxicity of the active ingredient(s) (summary, cf. enclosure)

5.1 Acute oral LD50 in the rat
5.2 Acute dermal LD50 in the rat
5.3 Acute inhalation LD50 in the rat
5.4 Skin irritation, rabbit
5.5 Eye irritation, rabbit
5.6 Sensitizing effects, guinea pig
5.7 Sub chronic toxicity
5.8 Chronic toxicity
5.9 Carcinogenicity
5.10 Mutagenicity
5.11 Teratogenicity
5.12 Effects on reproduction
5.13 Supplementary toxicological studies (neurotoxicity, potentiation, accumulation, depending on the nature of the substance)
5.14 Metabolism in animals

6. Information on residues (summary, cf. enclosure)

6.1 Metabolism in plants
6.2 Behaviour of the residues in plant
6.3 Method of residue analysis (details, cf. enclosure)
6.4 Maximum residue limits (MRL)
6.5 Withholding period

7. Effects on wildlife (summary to be enclosed)

7.1 Toxicity to birds
7.2 Toxicity to fish
7.3 Toxicity to bees and other pollinating insects
7.4 Toxicity to other organisms, for instance beneficial insects

8. Behaviour in the environment (summary to be enclosed)

8.1 Degradation in the soil
8.2 Mobility in the soil
8.3 Absorption/desorption by the soil particles
8.4 Half-life in the soil
8.5 Behaviour in the water

9. Therapy and precautions.

9.1 Poisoning symptoms
9.2 First-aid measures
9.3 Antidote
9.4 Safety measures
9.5 Disposal of surplus pesticides and pesticide containers

10. Packaging profile

Size and type of packaging (details to be enclosed) and label draft

11. Registration status in other countries

Reference to the countries where the product has been registered, preferably EEC or OECD countries (copies of the registration certificates to be enclosed)

12. Biological dossier

separate dossier Date and signatures

ENCLOSURES

1. Composition of the formulated product
2. Analytical method for the formulated product
3. Analytical method for the active ingredient(s)
4. Method of residue analysis
5. Absorption spectra, IR, UV etc
6. Toxicological evaluation of the active ingredient
7. Assessment on behaviour in the environment
8. Assessment on toxicity to wildlife
9. Assessment on the residue situation in the requested crops
10. Product data sheet (2-4 pages of general information on the product, particularly precautions for safe handling)
11. packaging specifications
12. Copies of registration certificates in other countries

NB: Informations required in

- French for French speaking countries
- French and English for bilingual countries

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