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EAP Publication - 22

PREVENTATIVE PEST CONTROL

Stuart B. Hill, Ph.D.

Associate Professor of Entomology

Director of Ecological Agriculture Projects

Macdonald College

Ste-Anne de Bellevue, Quebec, Canada

Today, pests are usually seen as enemies and pest control as the use of science and technology to repress them. While great successes have been achieved by following this approach, there have also been numerous disbenefits including damage to human health, to non-target species including beneficial organisms, and the development of additional pest problems. Recognition of this situation has led to the development of integrated pest management (IPM), an approach designed to retain the benefits of the previous methods of control and to minimize the disbenefits. Although progress has been made in this direction there remain Inherent problems, particularly because of the continued dependence of IPM on curative solutions. The alternative approach is to develop preventative solutions. Whereas curative approaches tend to be generated within disciplines, preventative solutions are transdisciplinary and involve the redesign of whole systems.

To understand this clearly I believe it is necessary to take an evolutionary approach towards the development of pest control. Indeed, the nature of the relationship between people and pests may be seen as an indicator of the level we have reached in the evolution of our own species. In this paper I will develop this argument and share with you the way in which my approach towards pest control has changed over the past ten years.

THE IMPORTANCE OF PEST DEFINITIONS

Pests comprise competitors of humans for resources, enemies, including those that transmit diseases, and nuisance organisms.

The pest status of competitors is usually defined in terms of economics. Thus, they are considered to be pests when it is economic to control them. This may reflect both rational and irrational criteria, such as cosmetic standards for the appearance of food. Enemies and nuisance organisms may also be controlled in response to both rational and irrational criteria. Weed free lawns and insect free recreational areas exemplify the latter. As such definitions reflect our values, it IS likely that by developing more rational values we will also generate a more rational definition of pests, and more rational approaches to their control or prevention. For example, by defining pests as indicator organisms of maldesigned and malfunctioning ecosystems, in our response to them we would be more likely to focus our attention on redesign and improved management than on the enemy the pest, and its elimination or control.

HISTORY OF OUR RELATIONSHIP WITH AGRICULTURAL PESTS

Moore (1967) has divided our past relationships with potential crop pests into four stages (Fig. 1): pre-agriculture, when pests rarely caused significant damage because of the ecosystem's natural complexity; pre-pesticide agriculture, when, with the simplification of ecosystems, pests followed cycles of outbreak and repression by natural controls; pesticide agriculture, when pesticide use was followed by pest resurgence and the development of secondary pests as a result of the repression of natural controls; and pesticide resistance agriculture, when pesticides became less effective because of their selection of resistant individuals within pest populations.

With respect to the future, Moore argues that we have three alternatives: continue to develop new pesticides (and therefore also new resistance); grow crops in enclosed artificial environments designed to exclude pests; and redesign agroecosystems to incorporate enough characteristics of pre-agriculture ecosystems to keep pest population densities below economic thresholds.

My own perception is somewhat similar to Moore's and is shown in Fig. 2. It describes what has happened and what I hope will happen in the future. Thus, the major development that is still taking place is an evolution from a control to a management philosophy, and from reliance on one or a few pest control strategies to the integration of many approaches into a system usually referred to as integrated pest management or IPM. The main advantage of IPM is that it has made the practice of pest control more "scientific" and more precise. In its refined form, it is based on a systems approach and is administered by a team of specialists from a diversity of disciplines. It has been particularly helpful in answering the following five questions (Fig. 3): is control warranted, when should it be applied, where should controls be applied, what mix of controls are appropriate, and how successful was the intervention?

The main problem with IPM is that it is still based on the perception of pests as enemies, and consequently it relies most heavily on curative solutions (see the upper part of Fig. 4). Furthermore, it fails to confront the causes of pest outbreaks (Fig. 5). Also, although it claims to be integrated, IPM still tends to take a linear approach (see the lower part of Fig. 6), and it fails to deal with the complex interrelationships between influencing variables (also shown in Fig. 6). Another view of IPM is that it largely represents an effort to use pesticides more efficiently and, where economic, substitute less environmentally disruptive approaches, such as biological controls (see lower left in Fig. 7).

 

 

It is becoming increasingly apparent that all IPM programs are severely limited by the designs and management strategies of present food and fibre production systems, particularly their uniformity, reliance on susceptible crop varieties, and tendency to cause stress to crops during the growing process, thus making them more attractive to pests and susceptible to damage (see upper left in Fig. 7).

EVOLUTION OF A PREVENTATIVE APPROACH TO PEST OUTBREAKS

If IPM is limited in its development, as I believe it is, then it is necessary to take a different approach. Such an approach was implied in the discussion of the definition of pest above (see also Fig. 2). Thus, if pests are viewed as indicators of maldesigned and malfunctioning systems, the requirement is to understand the causes of pest outbreaks and to modify the design and management of systems to prevent them.

In plant production the causes of pest outbreaks are associated with the main stages of production (left hand side of Fig. 5): plant selection, site selection and preparation, planting design, site maintenance, harvesting, distribution, storage and the timing of all operations.

Just as these practices are responsible for pest damage by influencing the properties of pests, their dispersal, availability of suitable food and space and by limiting the presence and effectiveness of natural controls (central part of Fig. 5) it is by the integration of changes in these practices that effective preventative methods of pest control are likely to be found (see also lower part of Fig. 4). Examples of specific factors to consider are listed in Fig. 8, and an artists impression of a more diverse, less pest-susceptible agroecosystem is shown on the right hand side of Fig. 7.

The aim of such an approach is to design systems that are capable of solving their pest problems "internally", as opposed to relying on direct interventions from outside. Thus, the system would be designed to contain sufficient feedback loops in the form of natural controls such that if a potential pest population began to increase, it would soon be repressed because of the constant availability of these natural controls. Furthermore the crops would be less attractive to pests, less stressed and less susceptible to significant damage.

For the full success of such an approach, we would need to take one further step in human evolution, and that requires the adoption of a value system that promotes a policy of production for need as opposed to production for demand (often greed'), i.e. this implies the design of sustainable, resource conserving systems that support rather than disrupt natural ecological processes fright hand side of Fig. 2).

The way in which pest control within such systems contrasts with that in conventional systems is shown in Fig. 9. This is a diagrammatic version of Fig. 7.

 

Thus, the degree to which conventional food systems are maldesigned and malfunctioning is the degree to which they generate problems, Including- pest outbreaks. Pesticides are conventionally used as curative solutions. Only a small percentage of the pesticide reaches the target organism, most contaminating the environment where unintended damage may result. Two solutions are generally proposed to reduce this problem: the efficient use of pesticides, achieved through pest monitoring and improved methods of pesticide application, and the substitution of less disruptive methods, such as biological controls. The problem associated with these "efficiency" and "substitution" approaches is that the more successful they are the more they protect and perpetuate the agroecosystem designs that are generating the problems. Furthermore, these designs have been established to meet both needs, which can be satisfied, and wants which are mostly compensatory for unmet other needs and therefore tend to be unlimited. As such they are resource consumptive, and degrading of person and planet. The proposed solution is the redesign of self and system: of the self to abandon compensatory and neurotic wants, and of the system to prevent pest outbreaks, as described above. Such a perception places humans within rather than on the outside of the systems being managed. The final stage in this argument must focus on how such an approach might be achieved, and this necessarily takes us out of the realm of entomology and into the realm of psychology.

PREVENTATIVE PEST CONTROL AND HUMAN PSYCHO SOCIAL EVOLUTION

Our current approach to pest control (also to food production) is not rationally derived in the present, it has a long history, in fact the whole of human history. While this inheritance is rich in its gifts, it is also restricting. For example, is it more rational to see pests as enemies and try to eradicate them, or to see them as indicators of maldesign and malfunction and try to correct the causes? While most of us can recognize the sense of the latter, we still tend to take dominantly curative approaches to pest problems. This conflict reflects a dichotomy deep within ourselves, between the reality that we know makes sense, and the pseudo reality that we have inherited through our upbringing. It is this pseudo reality that causes us to doubt reality and that keeps us powerless when confronted with irrational behavior. Most pesticide use, for example, is clearly irrational behavior, and most other curative approaches to pests, by not dealing with the causes, cannot claim to be much more rational. The bias of this strategy becomes more obvious when we consider pest control as just one example of our dominant approaches towards problem solving (Fig. 10). On the right of this figure are the common characteristics of most modern problem solving strategies. What are neglected are the equally important, if not more important, approaches shown on the left. It is easy to see from this list that a person who has been brought up in an oppressive way, and who consequently feels powerless, will be more likely to be attracted to the strategies on the right. This is because these are more likely to make the individual feel powerful, and appear powerful to others, even if it is only temporarily. While this is an oversimplification of the situation, it is my belief that such, largely hidden, forces determine much of what we do, in spite of our well practiced defense of our behavior as rational.

In Fig. 11 and 12 I have provided the essence of a more extensive argument that traces food system designs (including the methods of pest control) through our value systems, and human conditions, to our past experiences, particularly to the degree to which these were emotionally and physically stressful, and the degree to which experienced stresses or hurts were allowed to be healed in childhood, through such simple natural recovery processes as the provision of loving attention while a child is crying.

Common responses to propositions, such as the one I am making here, range from excitement in those who have also recognized that there is something fundamentally wrong with the way in which most of us live (and relate to pests), to objections that this has nothing to do with the subject, or even with science. I would caution any who fall into the latter category to risk considering this with an open mind, for if the psychologist R.D. Laing (1971) is correct, it will be predictably difficult to accept such a view as 1 am presenting. Laing claims that in our development, it is as if each of us were hypnotized twice: firstly into accepting pseudo reality as reality, and secondly, into believing that we were not hypnotized. Thus, defense of our psueodorealities is a common phenomenon, but it is also the primary barrier to further psycho social evolution of our species, and consequently to the development of more rational approaches to pests and their control.

CITED REFERENCES*

*LAING, R.D. 1971. The Politics of the Family. Pantheon Books, N.Y.

*MOORE, N. 1967. A synopsis of the pesticide problem.`Adv. Ecol. Res. 4: 75-129.

*OLKOWSKI, H. 1980. What is IPM? Practicioner 2(5): 3-4.

OTHER RELEVANT REFERENCES BY THE AUTHOR

HILL, S.B. 1978. Agricultural chemicals and the soil. Pp. 18-53 in Chemicals and Agriculture.

HILL, S.B. and P. Ott (ads.) 1982. Basic Techniques in Ecological Farming. 365 pp. Birkhauser, Basel, Switzerland.

HILL, S.B. 1984. Controlling pests ecologically. Soil Assoc. Quart. Rev. M

HILL, S.B. 1985. Redesigning the Food System: Sustainably. Alternatives 11(3/4):32-36

Copyright 1985 Ecological Agriculture Projects


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