5. Biological control in developing countries: towards its wider application in sustainable pest management.
Med. Fac. Landb, Rijksuniv. Gent, 55 (2a), 1990, pp. 217-223
Biological control is the use of living natural enemies - parasites, predators, pathogens - as pest control agents. The most attractive biological control technique is the introduction and permanent establishment of exotic species for long term pest suppression (known as classical biological control) because once in place no further input is required. Manipulations of the crop environment to enhance the impact of pre-existing natural enemies, referred to as conservation of natural enemies, may also provide long term control. When long term biological control is not possible, periodic applications of natural enemies may be made to achieve short term control by timed releases of native or exotic natural enemies to control pests over a season, or natural enemies may be applied as biological pesticides for immediate reduction of pest numbers. Usually more or less host specific natural enemies are screened to ensure that non-target organisms of economic importance or of conservation value are not harmed. In this way undesirable side effects are avoided and biological control has a minimum impact on the environment.
Biological control can provide a sustainable and environmentally acceptable pest management, often at little or no direct cost to the farmer and so it has many advantages, especially for the resource poor farmer in developing countries who cannot afford costly imported chemical pesticides.
Biological control offers more or less target specific pest control, which may be indefinitely sustainable at little or no recurrent cost.
Therefore, it should be attractive, not only as a means of solving major pest problems of overriding importance but also as one of the central components of pest management in specific cropping systems. World-wide surveys indicate that the adoption of biological control as a pest control strategy varies greatly between regions, countries and crops.
Some reasons for this uneven uptake are discussed in this paper.
Unfortunately biological control research does not receive the level of institutional and financial support given by chemical industry to the development, promotion and marketing of pesticides. The production and distribution of high yielding varieties of major crops is well supported, especially by the International Agricultural Research Centres and by industry.
The different approaches to applying biotic agents in pest control are reviewed in relation to their appropriateness to the various agricultural production systems found in developing countries, e.g., plantations, cash crops, horticultural crops, subsistence farming. Some constraints to the wider application of biological controls are outlined; notably misconceptions over the mode of action of biological control agents and their safety, pressures to rely on chemical pesticides, lack of administrative support to facilitate implementation of biological controls and inadequate investment in research and development. Some current initiatives by various agencies to find ways of overcoming these constraints are discussed.
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Review, biotechnology, transgenic plants, insect pests, pesticides, crop yield, genetic engineering, inherent resistence
HILDER, V.A. and A.M.R. GATEHOUSE
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