Entomology Today | Robert K.D. Peterson, Ph.D. | Article Link
While the ideal of integrated pest management has been pursued and adopted in a variety of settings since the mid-20th century, recent trends point to perhaps too great a focus on killing pests rather than managing host stress. In a new paper in American Entomologist, three experts suggest a modified focus that better accounts for evolution and tolerance to pest injury and shifts from control toward management. (Photo credit: Howard F. Schwartz, Colorado State University, Bugwood.org)
Whatever happened to integrated pest management?
If you’re a regular reader of Entomology Today, you might think “Why, I didn’t know anything hadhappened to it.” So, why is anyone even asking this question?
It’s true that integrated pest management (IPM) is a term well known. It is used liberally by scientists and other practitioners without the need for definition, and it is a major success story for society. But it can also be argued that IPM has, in fact, lost its way.
There has been little formal discussion of IPM theory and its status over at least the past 10 years, even though in that time we have seen both the overwhelmingly successful adoption of prophylactic pest control tactics in the form of transgenic crops and seed treatments and the increasing application of evolutionary biology in environmental and public health management.
The time has come to revisit the foundations of IPM and look deeply at its conceptual aspects and future development. To that end, in a forum paper in the latest issue of American Entomologist, my colleagues Leon G. Higley and Larry P. Pedigo and I present our case for a conscious evolution of integrated pest management. The article is provocative and therefore it is meant to generate further discussion in the entomological profession, and we hope you’ll read it, but here I’ll share a brief synopsis of our specific recommendations:
Initiating new dialogue and research on the central tenets of IPM, especially evolution.
Evolution holds a central place in pest management, yet its role in IPM has received relatively little attention. This is ironic because a chief impetus for the development of the integrated control concept in the mid-20th century was the reality––indeed, inevitability––of arthropod resistance to insecticides.
Managing pest resistance to tactics that impose strong selection pressures necessitates the need for applications of evolutionary biology, such as reducing phenotype–environment mismatches (i.e., when a population’s phenotypic trait distribution differs from the environmental optimum) and incorporating combinatorial approaches to sustain management of pests. We argue that IPM has a clear role to play here, provided that it is firmly connected to ecology and evolution.
Replacing control with management.
If we are to more formally and more completely incorporate evolutionary considerations into IPM, the emphasis needs to shift broadly and resolutely from killing pests to managing host stress, where possible. Control implies a heavy-handed program focused on the pests themselves, whereas management encompasses reducing host injury to tolerable levels in addition to modification of pest populations.
Thus, we propose an updated definition of pest management: “a comprehensive approach to managing host stress that is economically and ecologically sustainable.” This is similar to past definitions but additionally benefits from a focus on the concept of managing host stress as a way to incorporate evolution more formally in IPM. In our context, a host is the receptor of a pest’s activity or injury, so it can include plants or animals, including humans.
Initiating host breeding programs specifically to breed for tolerance to pest injury.
We need to systematically incorporate tolerance of pest injury into pest management programs. Tolerance, whether as a type of resistance or as an important concept of economic injury levels, ameliorates selection for pest resistance to tactics. We acknowledge, however, that breeding plants to be tolerant to pests is much easier said than done.
Emphasizing how to use tactics and de-emphasize the focus on tactics themselves.
We need to continue to move more pointedly from an emphasis on tactics to an emphasis on how to use tactics, which has direct implications for selection pressure and therefore for sustainable pest management. This focus has been largely overshadowed by the discovery of tactics and what we call the “have-technology-will-use” syndrome. Instead, by focusing on how to use tactics, we can ensure that we are incorporating evolutionary considerations into IPM. Current approaches to resistance management for antibiotic drug use in public health, for example, as well as for Bt crops in agriculture, have relevance for IPM.
Recommitting to and updating Kogan’s levels of IPM adoption.
In 1998, Marcos Kogan argued for three levels of IPM implementation as a way to encourage progression along increasing ecological, socioeconomic, and agricultural scales and complexity. We recommend that this scheme be used to reinvigorate IPM but also revised to incorporate our recommendations, such as by substituting “management” for “control” and added additional agricultural, socioeconomic, and ecological scales, among other changes.
We conclude the paper with a call to action: Our suggestions require a commitment to thinking about––and acting on––pests as part of the management of a system, with the host being central to that system. This is in contrast to the more common approach of focusing on the pest as the entity to be controlled. Although it comes with numerous additional challenges, we should be adaptively managing agroecosystems, urban ecosystems, and natural ecosystems, not attempting to control one or a few organisms within these systems.