The unifying theme of the NAS study is that all phases of agricultural pest management, from research to field implementation, should be evolving from its current product-based orientation to one that is based on ecological principles and processes. Such pest management practices would rely more on an understanding of the biological interactions that occur within every crop environment, and the knowledge of how to manage the cropping systems to the detriment of pests. The optimum results would include fewer purchased inputs (and therefore a more sustainable agriculture), as well as fewer of the human and environmental hazards posed by the broad spectrum pesticides so widely used today. The committee proposed the term Ecologically Based Pest Management (EBPM) to describe this approach to pest control.

A historical perspective. The report first provides an overview of the history of pest management in order to set the stage for the recommendations which then follow. Examples are provided of the importance of cultural controls (such as crop rotation and sanitation of infested crop residues), biological controls, and plant selection and breeding for resistant crop cultivars. Such practices were very important and widely used prior to the advent of synthetic organic pesticides; indeed, many of these practices are still used today as components of IPM programs. However, the great success of modern pesticides has resulted in their use as the dominant pest control practice for the past several decades, especially since the 1950s. The committee concluded that, although pesticides will continue to be a component of pest management, the following are significant obstacles to the continued use of broad spectrum pesticides in particular.

Resistance to pesticides. All groups of pests (insects and mites, weeds, and plant pathogens) have demonstrated resistance to various groups of pesticides. For example, the incidence of insect species known to be resistant to one or more insecticides increased from 14 in 1948 to over 500 by 1990.
Fewer new pesticides. The cost of developing new pesticide products is very high, and there has been a steady decline in new pesticides introduced since the 1970s. Many older materials are also being lost, through regulatory action or marketing decisions.
Pesticide-induced pest problems. Some broad spectrum pesticides have been shown to induce outbreaks of both target and non-target pest organisms, both directly and by elimination of beneficial organisms that would normally suppress the pest.
Lack of effective pesticides. Some pests, such as many that occur in the soil, are naturally difficult to control. In crops where there is a low monetary return per acre, the cost of pesticides may not be justified.
Human and environmental health concerns. Air, water, and food contamination by pesticides continues to be a concern of the general public. Farm worker safety has impacted how pesticides are used. Some pesticides cannot be used in areas where endangered species exist.

Defining EBPM and identifying needs for implementation. The fundamental goals of EBPM include (1) safety to humans and the environment, (2) assurance of profitability for the farmer, and (3) long term durability.

Implementation of EBPM relies on the knowledge that stability in biological systems relies on feedback between organisms. For example, as the numbers of one organism increase, the numbers of predators, parasites, and pathogens that attack that organism also increase. In the most stable systems, the amplitude of these oscillations are minimal; in agricultural systems this means that potentially damaging species usually never are abundant enough to become actual pests. As stated by the report (p. 43) "Because neither pesticides nor host-plant resistance methods are responsive to feedback, achieving stability and balance within the agroecosystem is not possible with those [methods], but is a fundamental goal of EBPM." Therefore, the report concludes that the use of living biological control organisms (i.e., biological control) is potentially the most important foundation for pest management. However, the committee realized that pest problems often may not be completely resolved using biological control, and therefore other compatible methods may also be needed. However, other methods must be selected and used with care so as to not disrupt the benefits of the biological control organisms. Also, from an economic perspective, purchased inputs should be replaced, when possible, with those management practices that are less expensive to implement. Purchased inputs that might supplement indigenous biological control include (1) purchased biological control organisms (for augmentation biological control, including living microbial pesticides), (2) biological control products, such as the natural toxin derived from Bacillus thuringiensis, (3) narrow spectrum synthetic pesticides, and (4) resistant plants, derived either from conventional breeding or genetic engineering.

In order for EBPM to be successful, pest managers must accept a paradigm shift from practices focusing on purchased inputs and broad spectrum pesticides to those using knowledge about ecological processes. EBPM will be more knowledge intensive than the use of pesticides, and will certainly require a different type of knowledge. If EBPM is not product-based, who will supply the information to farmers and other pest managers? The report identifies the public sector, such as university Cooperative Extension programs, as an important source for EBPM information, especially considering that the public sector is more likely to do the underlying research. However, the report also recognizes a significant need for private independent pest management consultants to transfer EBPM methods to the farmer.

Research needs. The committee recognized that EBPM technologies currently do not exist for many pest problems. Therefore, the report emphasizes the need to accelerate research and development to provide more specific tools to implement EBPM. Most of the discussion involves research needed on even the most basic ecological interactions that are currently poorly understood. Each cropping system offers different challenges for pest management, and must be studied independently. The report emphasizes that significant advances in the development and implementation of EBPM will come only as national research priorities change. As governmental agencies, such as the USDA and state universities, continue to face financial cutbacks it will be difficult to develop new research programs. Therefore, while private industry continues to develop product-based approaches to pest management, it will be increasingly difficult to make advances in EBPM without significant new funding in the public sector. However, the infrastructure needed for EBPM research currently exists at both national and state levels.

Public oversight. No technology is completely free of potential risk, including biological control and other approaches to EBPM. Appropriate safeguards must be in place for both research and implementation. The report discusses public oversight of ecologically based pest management. Potential risks to both humans and the environment are discussed, as well as the roles of appropriate regulatory agencies (especially USDA and EPA). The committee felt strongly that the regulatory agencies should work together to develop and publish a guide to risk assessment that could be used to insure some uniformity in the regulation of biological control organisms and supplemental products for use in EBPM.

Is EBPM truly new and different? There was considerable discussion within the committee as to whether EBPM truly represents a change in pest management direction for U.S. agriculture. Some committee members, myself included, feel strongly that this is a logical next step in the evolution of integrated pest management (IPM). However, others feel that the term IPM has developed a reputation as being primarily threshold-based use of pesticides, without truly integrating biological or other control methods. Therefore, the consensus of the committee was that a truly biologically-based pest management paradigm, based on a knowledge of ecological processes rather than broad spectrum pesticides, must be called something different from IPM, hence the recommendation of the use of "EBPM". We should not get bogged down in semantics. The important concept is that pest management needs to shift from being primarily based on broad spectrum pesticides but a redirection in national research priorities is necessary to make this shift.

Ecologically Based Pest Management: New Solutions for a New Century, is a 144 page hardbound book published by the National Research Council. Copies are available for purchase from National Academy Press, 2101 Constitution Ave., N.W., Washington, DC 20418.

- Dan Mahr, University of Wisconsin - Madison