16.3. Integrated pest management
Historically, integrated pest management (IPM) was promoted first during the 1960s as a result of the failure of chemical insecticides, notably in cotton production, which in some regions required at least 12 sprayings per crop. IPM philosophy is to limit economic damage to the crop and simultaneously minimize adverse effects on non-target organisms in the crop and surrounding environment and on consumers of the produce. Successful IPM requires a thorough know- ledge of the biology of the pest insects, their natural enemies, and the crop to allow rational use of a variety of cultivation and control techniques under differing circumstances. The key concept is integration of (or compatibility among) pest management tactics. The factors that regulate populations of insects (and other organisms) are varied and interrelated in complex ways.
Thus, successful IPM requires an understanding of both population processes (e.g. growth and reproductive capabilities, competition, and effects of predation and parasitism) and the effects of environmental factors (e.g. weather, soil conditions, disturbances such as fire, and availability of water, nutrients, and shelter), some of which are largely stochastic in nature and may have predictable or unpredictable effects on insect populations. The most advanced form of IPM also takes into consideration societal and environmental costs and benefits within an ecosystem context when making management decisions. Efforts are made to conserve the long-term health and productivity of the ecosystem, with a philosophy approaching that of organic farming. One of the rather few examples of this advanced IPM is insect pest management in tropical irrigated rice, in which there is co-ordinated training of farmers by other farmers and field research involving local communities in implementing successful IPM. Worldwide, other functional IPM systems include the field crops of cotton, alfalfa, and citrus in certain regions, and many greenhouse crops.
Despite the economic and environmental advantages of IPM, implementation of IPM systems has been slow. For example, in the USA, true IPM is probably being practiced on much less than 10% of total crop area, despite decades of Federal government commitments to increased IPM. Often what is called IPM is simply “integrated pesticide management” (sometimes called first-level IPM) with pest consultants monitoring crops to determine when to apply insecticides. Universal reasons for lack of adoption of advanced IPM include:
- lack of sufficient data on the ecology of many insect pests and their natural enemies;
- requirement for knowledge of EILs for each pest of each crop;
- requirement for interdisciplinary research in order to obtain the above information;
- risks of pest damage to crops associated with IPM strategies;
- apparent simplicity of total insecticidal control combined with the marketing pressures of pesticide companies;
- necessity of training farmers, agricultural extension officers, foresters, and others in new principles and methods.
Successful IPM often requires extensive biological research. Such applied research is unlikely to be financed by many industrial companies because IPM may reduce their insecticide market. However, IPM does incorporate the use of chemical insecticides, albeit at a reduced level, although its main focus is the establishment of a variety of other methods of controlling insect pests. These usually involve modifying the insect’s physical or biological environment or, more rarely, entail changing the genetic properties of the insect. Thus, the control measures that can be used in IPM include: insecticides, biological control, cultural control, plant resistance improvement, and techniques that interfere with the pest’s physiology or reproduction, namely genetic (e.g. sterile insect technique; section 16.10), semiochemical (e.g. pheromone), and insect growth-regulator control methods. The remainder of this chapter discusses the various principles and methods of insect pest control that could be employed in IPM systems.