Nematode Control and Nematicides: Developments Since 1982 and Future Trends

Abstract

This chapter focuses on chemical control to manage nematode pests. Since chemical control dominated and is still the main approach to combat nematode pests, the development of the nematicide market in South Africa is described, notably since 1982. During this period a wide range of products from established chemistry were tested, resulting in six fumigant active reagents, five organophosphates, three carbamates and furfural (a low-toxicity plant derivative) being commercially available and registered for use. This expansion was led by a few key research workers who significantly expanded our knowledge of the nematode pest problems. Currently there are over 50 crop-related nematicidal end-use descriptions registered for use in South Africa, including one containing abamectin as the active substance that is specifically registered for nematode control on maize. The increase in control options has ran concurrently with increasing consumer and regulatory pressure to restrict the use of these environmentally harsh products. This has been mainly driven from the export-orientated produce markets, but local pressures have also developed as indicated by the withdrawal of aldicarb and the scheduled withdrawal of methyl bromide. The chemical industry has recently achieved some successes in meeting these pressures, and a number of new products and application techniques are in the final stages of development. These products have a reduced application rate, are environmentally more benign and have a favourable toxicological profile. In terms of biological control, an overview on the few products that are registered and used locally is given. These include products that contain mainly bacteria and fungi as the active substances. Although this management strategy has been applied to a limited extent in South Africa in the past, its use is expanding.