Scott H. Hutchins, Ph.D.
DowElanco
9330 Zionsville Road
Indianapolis, IN 46268
317/337-4971
shhutchins@dowelanco.com
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Integrated Pest Management (IPM) is uniformly recognized as one of the most useful and productive concepts in modern agriculture. Regretfully, however, IPM "implementation" often is cited as a pressing need to abate the perceived rampant use of pesticides. IPM is not - and never has been - a tool to reduce the use of pesticides. Rather, IPM is a rational approach to the incorporation of available economic and biologic data in an objective manner to assess the relative costs and benefits of pest control.
Stern and his coworkers at the University of California are credited with the first introduction of IPM as a concept with their paper in 1959 describing The Integrated Control Concept. This landmark work documented the principles of ecological balance as a viable agricultural concept and argued that insect pests, like all animals, are subject to population control by natural enemies and this benefit should be accounted for prior to the use of artificial control mechanisms. Further, they argued that only when the pest population exceeds an "Economic Injury Level" will control costs be justified as a sound financial practice.
Over a dozen years after the pioneering work of Stern et al., Stone and Pedigo first demonstrated the economic and biologic formula for calculating EILs and presented research methodology as the basis for transforming "theory" to "practice". Specifically, they demonstrated that the financial "break-even" point could be represented by a Gain Threshold (GT):
|
Control Costs ($/Acre) |
So, for example, if control costs of any tactic are $12/acre and the market value of the crop is $4/bushel, the gain threshold would equal 3 bushels/acre. In essence, this physical yield represents the amount of tolerable loss before the specific control tactic is financially worthwhile.
Once the deminimus yield loss is established, calculating the EIL is a matter of relating the injuriousness of the pest population to the GT level of loss. The EIL formula is stated as follows:
EIL (insects/acre) = |
Gain Threshold (bushels/acre) |
Although simple in concept, defining this biologic relationship has been exceedingly difficult due to a limited degree of knowledge about the injury potential (I) of many pests (i.e., how much plant tissue can a single insect consume over its life) and a highly variable host response to injury - or damage (D) -- based on generally unpredictable environmental circumstances. Pests that defoliate soybeans, for example, have a net effect of consuming 0.21 grams of harvestable grain per larva during "average" production years, but the same insect in "stressful" (e.g., drought) years results in a 0.46 gram loss. The management dilemma is which EIL to use: the "average" year EIL of approximately 173,000 larvae/acre or the "stressful" year EIL of only 79,000 larvae per year? Choosing the wrong EIL in either instance will result in an income penalty.
In summary, the EIL concept is the foundation for IPM and puts the key financial and biologic components in perspective to ensure decision making associated with individual pest control tactics is objective.
A precise and uniformly accepted definition of IPM has been elusive. Two key criteria, however, seem to prevail in most discussions of IPM:
Note that these two qualifying attributes require that the economic and biologic information necessary to be OBJECTIVE are considered in the context of producer values. There is NO preference given to one class of tactics over the other, except where value can be demonstrated.
With real-world implementation of IPM using the above criteria, several by-products may emerge. Perhaps the most commonly touted by-product is the reduction in pesticide (or other tactic) inputs -- and indeed this can and has happened in many instances. However, just as likely may be the by-product of more pesticide (or other tactic) inputs as a result of better understanding and realization of the injury (I) or damage (D) potential for pests. A third by-product, understanding the income risk that pests pose, will establish the "needs assessment" to objectively evaluate all tactical management alternatives. Although the by-products of IPM implementation can be significant - it is important to emphasize that they are by-products - not qualifying attributes. A valid IPM program does not have to decrease pesticide inputs to be an IPM program - indeed, the inputs may increase and still be considered IPM.
As a result of the confusion between qualifying elements and by-products, IPM is experiencing an Identity Crisis. Within academia and many branches of government, IPM has become somewhat of a "buzzword" used to convince granting agencies that their research proposals have merit as a means to the misguided goals of reducing pesticide use. And, although, many of the proposals do in fact relate to the key EIL biologic variables of injury (I) and damage (D), many more do not and contribute to the confusion and diffusion of IPM research objectives. In addition to academia, IPM also experiences a socio-political identity crisis - there is an errant belief that IPM is an "acceptable" public policy to reduce pesticides without the outright prohibition. Obviously, this identity is clearly wrong and not consistent with the management objectives or qualifying elements of the concept and practice.
In order to be truly sustainable, IPM must be supported as a sound financial enterprise represented through value-added services and products. Indeed, this is the most significant hurdle and places product and service organizations in the driver's seat with regard to accountability for IPM implementation.
These principles - supported by a financially viable pest management industry (products and services) -- will ensure sustained implementation of IPM. Without them, IPM is another short-term public initiative borne out of sociopolitical circumstances and artificially motivated through public grants.
With IPM products and services key to implementation, the American Crop Protection Association (ACPA) can provide critical leadership for sustained IPM implementation:
At the next level, IPM will continue to emphasize best business practices and encourage more focus on risk management (versus uncertainty) with regard to mitigating pests. Technology will accommodate this shift through development of tactics that emphasize pest avoidance where pests are generally considered as fixed costs. Where pests are variable costs of production because of their secondary or occasional pest status, curative products and solutions will continue to be preferred.
Integrated Pest Management is a concept and practice based in science and good business practice. For pest management to be considered IPM, two qualifying conditions must be met: objective value-based decision criteria are used (the economic-injury level is the basic concept) and multiple tactics are considered for use with an understanding of their respective features and interactive relationship. Both of these qualifying elements are perfectly aligned with the goals and ethics of ACPA and the member companies. Accordingly, ACPA can and should "do the right thing" through influence with research, organizational leadership, product design, and service business linkages. These activities will reinstate the value-added aspects of IPM and serve to minimize the current identity crisis.
Bottom line, ACPA should be at the head of the table with government, academia, commodity groups, and service industries in a proactive approach to reinstate the objective identity for IPM and drive the implementation process as a national priority.
Boehlje, M.D., and V.R. Eidman. 1984. Farm Management. John Wiley & Sons, New York, 806 pp.
Hutchins, S.H. 1995. Free enterprise: the only sustainable solution to IPM implementation. J. Agric. Entomol. 12:211-217.
Norton, G.W., and J. Mullen. 1994. Economic evaluation of integrated pest management programs: a literature review. Va. Coop. Exten. Publi. 448-120, Virginia Polytechnic Institute and State University, 112 pp.
Pedigo, L.P., S.H. Hutchins, and L.G. Higley. 1986. Economic-injury levels in theory and practice. Ann. Rev. Entomol. 31:341-368.
Stern, V.M., R.F. Smith, R. van den Bosch, and K.S. Hagen. 1959. The integrated control concept. Hilgardia 29: 81-101.
