Although pesticides provide benefits in our battle to control pests that destroy more than a third of all food, the use of pesticides also results in significant costs to public health and the environment. As many as 500,000 humans are poisoned annually by pesticides in the world; the United States alone reports about 45,000 human pesticide poisonings.

Pesticides have also caused many detrimental effects on agroecosystems and natural ecosystems. These include: (i) reducing and sometimes eliminating beneficial natural enemies that keep pest populations at low densities; (ii) increasing or decreasing reproduction in various animal populations; (iii) altering decomposition rates of soil organic matter; (iv) developing insecticide resistance in pests, which results in increased pesticide use and additional crop losses; and (v) eliminating honey bee and other bee populations in certain regions thus reducing crop yields and quality. Pesticides also have had major impacts on fish, bird and mammal populations.

Chemical pesticide technology has spread much more quickly in the developing world than has the capability to ensure its effective and safe use. Use of pesticides in developing countries is rapidly increasing, and pesticide exporters from the industrialized nations are increasing their sales to the developing countries. Many pesticides considered too dangerous for unrestricted use in the western nations are being exported from these nations to the developing world. Yet under current law it is perfectly legal for companies to export them. Some developing countries have not enacted legislation to govern the importation, domestic use and disposal of these or other pesticide materials. Even with the laws, the governments frequently lack the infrastructures required to enforce them. Further, the developing countries seldom have the medical personnel and facilities required for diagnosing and treating cases of pesticide poisoning, and programmes to train farmers on the correct use of pesticides and alternative methods are often inadequate.

This paper discusses ways that governments at national and international levels influence the spread and use of pesticides in the developing countries through legal action, policies on export and import, aid, research and extension, pest control programmes, and other means.

This study investigated Zambian importation, distribution and use of agricultural pesticides.

Data was collected by interviews, questionnaires and direct observation at international, national, warehouse and user levels. A wide range of pesticides is available. Imports and distribution are controlled by a few multinational companies (MNC's). No government control exists on types or amounts imported, and on distribution, packaging or labelling. Safety information is virtually non-existent. Some Zambianused pesticides are under restriction in the West. The total amount used seems to be increasing. Harmful health effects have been observed. The number of involved MNC's appears to be increasing.

The largest amount of imported pesticides is used by government in large scale medical and agricultural control schemes. In agriculture, large-scale farmers use most pesticides, but small-scale farmers are now beginning to use greater amounts and more types.

Most MNC's see this latter sector as a large future market. Most farmers get pesticide information only from MNC's. By comparison, the Extension Service is inadequate. Consequently, the authors suggest that the following are needed: A broad based Zambian advisory committee on pesticides; government legislation of importation, distribution, packaging, labelling and safety; and Extension Service expansion.

This paper considers the status of pests and pesticides in Mauritius, including pesticide legislation and flow.

Climatic factors, namely altitude, temperature and rainfall, influence the spatial and seasonal distribution and population dynamics of economically important pests as well as their hosts (crops and livestock). The case histories of a few selected pests (leaf miner, fruit flies, stable flies), their control measures as well as research efforts in this connection are reviewed.

An appraisal is also made on some aspects of pesticide legislation along with the distribution pattern of pesticides, in relation to pesticide management. The setting up of a recent Pesticides Management Advisory Committee is regarded as a move in the right direction to safeguard pesticide misuse and abuse. Food crop production is at the expense of huge pesticides input. A series of recommendations are made with a view to improving pesticide practices in the country.

The paper is a report of an on-going investigation into the quality and quantity of pesticides imported into Uganda and how candidate pesticides for importation are selected. Also under investigation is the method of distribution of the pesticides from importers to farmers and their management at the farm.

The investigation reveals that owing to improper documentation by the importers, it is at present virtually impossible to establish the quantities of pesticide imports. The study also shows that the present system does not allow for proper supervision of the quality of pesticides used in the country. It highlights the need for revision of the laws and setting up of an infrastructure to facilitate this supervision.

The study shows that although most farmers would be conscious of the toxicity of these pesticides, they are largely unaware of the possible long-term effects of poor handling of the pesticides, both to themselves and to the environment.

This study presents an interpretation of the way the Punjabi farmers in a village of the arid Sind perceive the pest hazard and the methods of management that they employ to deal with this situation. It is found that farmers do recognize the seriousness of the problem which consequently leads them to employ traditional as well as pesticide treatment of their crops. But because of financial handicap and other factors, they do not use pesticide regularly or in adequate quantity. As a result the control of pests remains ineffective.

Two questionnaire-based surveys were carried out amongst the small vegetable planting community in order to evaluate the effectiveness with which pesticides are being used and the ensuing health and environmental hazards. Good practice was assessed by a certain number of indicators based on various parameters. Data on health hazards were obtained from cases of poisoning and from surveys on blood cholinesterase levels.

The results give pertinent indications on pesticide flow, usage and perception. Generally, aged planters tend to adopt good practice, especially if they have had at least primary education, in which case they would seek advice. Many planters however do not get advice from the right source with regards choice of pesticides and dosage, although a significant proportion of planters do not follow recommended dosages. About three-fourths of the planters frequently resort to cocktails of two or more pesticides. Safety intervals are simply not observed by a good majority of growers. Measuring and protective devices, washing of spraying equipment, disposal of empty containers, and the types of pesticides stores leave much to be desired. The practice of mixed cropping leads to the use of a wide range of pesticides for the control of a single pest on various crops. There has recently been a general shift in pesticide usage with the introduction of synthetic pyrethroids. The misuse and/or abuse of pesticides has serious repercussions on the health of those exposed to such toxic chemicals, and cases of poisoning too are increasing. Remedial measures are suggested.

The ability of peasant farmers in the third world to monitor environmental occurrences around them has often been ignored. This study looks at Nigerian fanners' perception of pests and pesticides and determines the relevance of such knowledge as an input to efforts to devise effective integrated pest management strategies.

Farmers in Kabba area of Kwara State, Nigeria were extensively interviewed and the following findings were highlighted: they had a deep knowledge of all insect, animal and fungi pests; could identify each pest, know their breeding cycles and their general behaviour characteristics; were able to make a relatively accurate assessment of damage caused by pests; and developed an indigenous integrated pest management strategy.

Due to massive pest damage in the last few years, and strenuous advertisement by the Ministry of Agriculture, many farmers are now turning to chemical pesticides for solution to the pest problem. Prognosis of future trends in pesticide usage among farmers reveal the likely danger of farmers becoming pesticide-dependent with the consequent possibilities of human poisoning and eventually aggravating the pest problem.

The main pest control tactic employed by the farmers in Tanjong Karang is the application of pesticides. The fanners seem more aware of the need to spray their crops. No fixed spray schedule is being adhered to. Most farmers spray when pest damages are observed. Three to four applications per season are usually used and most farmers spend less than M$100 (US $43) on chemicals in a season. Chemicals are usually bought with cash from chemical sales representatives.

More than half of the farmers rank rats as their most important pest (56.5%) and more than a quarter (27.2%) rank stem-borers as their most important pest. It is felt that farmers tend to mention these two pests, especially stem-borers, when they are being asked, as these are the “traditional” pests and their damages are usually visible.

In the main season 1980/81, 43.5% of the farmers reported serious pest damages in their fields. All these farmers attempted to control the pests using chemicals. However, only 27.5% of them felt that they had succeeded. This clearly suggests the need for better pest control practices to be implemented in Tanjong Karang.

In many tropical countries, increasing use is being made of irrigation to grow more food for the world's expanding population, but as well as bringing benefits irrigation also causes problems. The proliferation of standing water provides numerous habitats for snail intermediate hosts of schistosomiasis and mosquito vectors of diseases such as malaria and filariasis. Thus, while irrigation schemes can be successful in providing more food they may be accompanied by increases in vector-borne diseases. In some schemes resettlement of people creates overcrowding and slum conditions which can result in a deterioration in general health and hygiene, facilitating the spread of water related diseases such as cholera, typhoid and various dysenteries. Efficient vector control, supported by the people, is needed to reduce the undesirable effects of irrigation.