1.1 Introduction

Chemical pesticides are synthetically produced compounds to control various kinds of unwanted organisms - weeds, fungi, mites, insects etc. In this booklet, such organisms will collectively be referred to as pests.

Plant diseases resulting in reduced crops is a common problem in agriculture. When chemical pesticides were introduced in the 1940s they were regarded as a major achievement. Pesticides were introduced in the developing countries as part of "the green revolution" where the objective was a growth in agricultural production. The pesticides were relatively inexpensive and highly effective, and soon it became common practice to spray all crops regularly throughout the growing season, even when there were no visible signs of diseases. Since then, the considerable environmental impacts of pesticides which may occur have become apparent. We also know that pesticides often lose some of their effect when used for long periods of time. Many pests have become resistant to pesticides and are therefore very difficult to control.

These observations have lead to increased efforts to find alternative pest management methods to chemical pesticides. One of the alternatives, the so-called IPM, or Integrated Pest Management, has gained considerable attention.

However, it does seem unlikely that all use of pesticides will end in the future. New methods and regulations for the secure use of pesticides are constantly being developed, encouraged by a number of international regulations and recommendations. One prominent example is the collaboration between FAO and WHO on plant protection management. These two organisations have compiled a list of the maximum pesticide residue limit of various nutrients. FAD/WHO Codex Alimentarious Commission is an international forum for food safety. The Commission concerns itself with industrial pollution, additives, heavy metals, mycotoxines, pesticide residues and other xenobiotics in nutrients. A special committee, the "Codex Committee on Pesticide Residues" determines the so-called Maximum Residue Limit for pesticides in nutrients. The residue limits set by the Codex Committee have been accepted in most countries.

Yet another example of international regulations and recommendations is the 1985 FAO conference, where an "International Code of Conduct on Distribution and Use of Pesticides" was passed. The background for this was the fact that many developing countries lack an infrastructure for pesticide approval. This is the reason why FAO gives priority to national programmes for pesticide control, which will result in better security for the persons handling the spraying, as well as for the consumers.

Countries which do not have a pesticide control agency, will have to rely on the importing agencies with regard to safe distribution and use of pesticides. In some cases, pesticides which no longer have official approval in developed countries are still being distributed in developing countries. This must be stopped. The safe use of pesticides requires knowledge about official approval and distribution as well as storage and the application of the pesticides. Many developing countries lack an administrative agency to select relevant pesticides, as well as sufficient training of personnel to handle them. This situation makes safe handling and use of pesticides more difficult.

This booklet emphasises a description of possible environmental impacts from the use of pesticides. However, alternative nonchemical agents will also be considered. The main focus is on agricultural plant protection, and the use of pesticides in other contexts is dealt with only very briefly.