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“Built-in” Pest Management

Welcome to Book of the Week – a weekly feature offering you a glimpse between the pages of an Acres U.S.A. published title. Get the Book of the Week email newsletter delivered directly to your in box! This week’s Book of the Week feature is A New Farm Language, by W. Joe Lewis.

“You can’t have any good guys without a few bad guys. That’s fact.”

So says Alton Walker. Alton and I have been friends since our days at Mississippi State where we went through our master’s degree program at the same time. Also a native of Mississippi, Alton continued his education at Clemson University, obtaining a Ph.D. in entomology prior to his career in agricultural consulting and farming in Georgia. He and I came to have a shared interest in ecologically sound farming, and in the mid ’90s we collaborated with a team of scientists on sustainable cotton production following the boll weevil eradication. Alton is a scientist with some skin in the game. He’s pursued the application of his conservation/ecologically based ideas with cotton production on a 600-acre portion of his own farm.

As Alton will tell you, the common practice of cleaning a field down to bare soil after harvest and leaving it barren over the winter is a harmful practice for multiple reasons, including pest management as well as natural resource conservation. “Farming’s been the victim of the advances of highly mechanized ‘big farming’ approaches,” he says. “Through the use of large equipment like harrows, plows, and mowers, enormous portions of biomass are removed from countless stretches of land. The land is then tilled and planted into monocultures from ditch bank to ditch bank. Then, mechanical cultivation and chemical pesticides are used to restrict diversity, while fertilizers and irrigation foster a lush growth of crops. Every year, the process starts over, meaning there’s never an opportunity for a true, natural ecosystem to develop and remain in place for the length of time it takes for it to become balanced and efficient. It’s no wonder pest outbreaks occur. On the other hand, perennializing the field—growing something year-round—helps promote a much more stable and balanced environment. We have to find our way back to approaching farming, including pest management, with an understanding of how to manage the ecosystem in which we live.”

The team Alton and I collaborated with in the ’90s was an interdisciplinary group of researchers that included Sharad Phatak, Rick Reed, John Ruberson, and Jim Hook, and Glenn Harris with the University of Georgia, and Philip Haney with my laboratory in Tifton. Eradication of the boll weevil, which had been completed in Georgia in 1990, and, later, essentially all of the United States, presented the cotton industry with a unique opportunity to advance sustainable agriculture. The eradication had been one of the greatest technical successes in agricultural history, with immense potentials in economic and environmental benefits. To completely eradicate the presence of a pest of this magnitude from the entire cotton belt! In Georgia, insecticide use was already dropping sharply, with average crop revenues increasing markedly. By 1995, the use of fifteen to twenty treatments per year had been reduced to three to five treatments. Grower interest in biological control and sustainable agriculture had never been higher, but a shift in thinking on when and how to give nature more time was going to be needed. The boll weevil had been an invasive pest without any effective natural enemies. Quick to reach damaging levels in early season, it was an especially devastating primary pest because the necessary insecticidal treatment for its control regularly spurred a sequence of secondary pest outbreaks. But now, for the first time, we could put in place an ecologically based management system without the disruptive influence of the early season boll weevil treatments.

In this new era, we could promote the adoption of cotton production as part of a healthy year-round landscape system, with approaches to pest management that deal with the natural enemy/pest complex being a vital part of that overall system.


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But to take advantage of this new era, we knew there needed to be a lot of educational outreach to the grower community, including on-farm demonstrations with associated data. Otherwise, we could miss the opportunity and drift back to pesticides as the dominant pest-management practice.

Figure 9a below shows the conventional high intervention methodology (Box 1) as contrasted to year-round landscape ecosystem management (Box 2). The conventional, high-intervention approach has predominated cotton production and pest management for years, particularly since the advent in the 1950s of big farming. After harvest, the field is mowed and harrowed, rendered barren until spring when the process starts over. Because of this winter and early spring “wipeout” of everything prior to planting, the ecosystem—as represented by the typical “ecological growth curve”—is never able to achieve equilibrium status. So, there are no relays of natural enemy/pest balances into the following season. As one consequence, the pests show up first with a lag time before the natural enemies can be expected.

During the growing season, the crop is kept clean of pests such as weeds, insects, and other undesired variables by thorough cleaning, pre-planting tillage, and other soil preparation and operations, and by diligent mechanical and chemical interventions during the growth and fruiting phase. Use of fertilizers, irrigation, and other inputs are used to ensure a lush, mono-cultural growth of cotton plants from one end of the field to the other. Other plants are considered undesirable and out of place. So, this lush abundance of cotton plants, without alternate vegetation as food sources and shelter for the natural enemies of pests, along with high frequency of mechanical and chemical intervention, creates an environment prone to disruption and resistance, ultimately leading to the pesticide treadmill. This is why, prior to the boll weevil eradication, the number of pesticide treatments for cotton production would sometimes approach twenty per season.

Moreover, the lack of winter cover and the high-intervention approach with substantial removal of the biomass, along with frequent harrowing and tilling, contribute to heavy depletion of organic matter and soil microbial quality, plus extensive water and wind erosion. All of this leads to a host of other issues including lower air and water quality; higher use of fuel, labor, and machinery wear; soil compaction; and the loss of associated wildlife.

Yes, after the boll weevil eradication, we had the opportunity to shift to a less disruptive, environmentally sound, sustainable approach as represented above (Box 2), but it was going to take some time and outreach to bring about such a change in practice. We were up against methods of farming that had dominated pest management in every cropping system for over sixty years. Rachel Carson’s call for concern had brought about change, but the change was to move to softer, less toxic pesticides. Still treating the symptoms, in other words. But we had come to understand that the real issue stemmed largely from a lack of understanding of how and why external interventions are disruptive and unsustainable, in contrast with sustainable “built-in” mechanisms, which we had concluded should always be the first line of defense.

I began having discussions about this lack of understanding with Sharad Phatak, a respected pioneer on the subject, and from whom I had gained much insight. We decided to present our case as a profession-wide argument in a highly respected publication. In 1997, he and I, along with Joop van Lenteren and Jim Tumlinson, published a paper in the esteemed journal Proceedings of the National Academy of Sciences of the United States of America (Proc. Natl. Acad. Sci. USA). Our paper, “A Total Systems Approach to Sustainable Pest Management,” stressed the urgent necessity for a fundamental shift in how we think about and approach agricultural pest management to resolve escalating economic and environmental problems. We drew on our discoveries to show that an ecosystem is just that—a system, with interactive parts that behaves not like a collection of unrelated pieces, but more like a living organism. We emphasized what we’d learned about the remarkable built-in mechanisms that agricultural ecosystems have, mechanisms that act through a set of feedback loops to maintain balance and to protect against herbivore feeding, diseases, climatic stress, chemical imbalances, and other similar attacks or interventions. To our great satisfaction, the paper turned out to be a major factor in reshaping foundations around sustainable agriculture at grower, research/education, and policy levels. The USDA Sustainable Agriculture and Education Agency adopted the paper for nationwide use as a standard in guiding constituents toward grant proposals and used it as a standard in developing a sustainable pest management brochure.

The gist of our argument then (as now) centers on the obvious contrast between our sustainable approach making use of the built-in defenses, and the interventionist “treadmill” approach. Figure 9b further illustrates this contrast. The built-in defenses respond only when, where, and at the level needed. They are need-induced and target specific. The chemical SOS signals sent by plants under attack are a perfect example of this. Parasitic wasps searching for these plant feeders, thereby rescuing the plants in distress, create pest control only in fields and around plants with actively feeding populations of caterpillar pests, thus avoiding non-target collateral damage and disruptions.

Furthermore, these parasite-host/predator-prey interactions are free of resistance and maintain balance, within fluctuating bounds, through a density-dependent phenomenon, meaning that levels of attack are determined by the availability of hosts or prey. On the other hand, external therapeutic interventions, such as applications of pesticides, act continuously at full level throughout the field without regard to need or target. The consequence is high collateral damage and disruption, and maximum selection for resistance. Next stop: the pesticide treadmill.

The interventionist approach is engrained deeply into not just the agricultural mentality, but in the way we, as a society, think about corrective actions in any system. You can observe the same treadmill effect in how we approach the health of the human body. On the surface, it seems that the proper corrective action for an undesired entity is to apply a direct external counter force, hence a “healthy” dose of antibiotics for infections or painkillers for pain. But there’s now a long history in medicine where it can be demonstrated that such interventionist actions never produce sustainable desired effects. They always become less effective requiring more and more to get results. The attempted solution eventually becomes the problem. You can find vivid examples with the growing resistance to antibiotics, and problems of addiction stemming from drugs for treatment of pain or mental distress. Black-market crime is on the rise as people seek illegal sources of drugs, just as it rose during the days of prohibition as an intended solution for alcoholism.

As a matter of fundamental principle, the application of external corrective actions into a system can be effective only for short-term relief. Long-term, sustainable solutions can only be achieved through a shoring up or restructuring of the natural system—in the case of the body, through nutrition, sleep, exercise, etc.—so that natural built-in forces, such as the immune system and other regulators that function on an as-needed basis, act effectively.

The same thing is clear with pest control strategies centered on toxic chemicals and other therapeutic interventions, such as prophylactic treatments. New and “better” pesticides are continually required, just as new and “better” antibiotics are continually required in the field of medicine. It’s a constant footrace with nature. The use of pesticides and other treat-the symptoms approaches are unsustainable and should be the last, rather than the first, line of defense. A pest management strategy should always start with the question, “Why is the pest a pest?” and seek to address underlying weaknesses in ecosystems or agronomic practices that have allowed organisms to reach pest status.

About the Author:

Dr. W. Joe Lewis is an award winning scientist, recognized worldwide for major crosscutting discoveries in the fundamental science of pest management. The models for his studies have been behavioral and chemical interactions of parasitoids, insect herbivores, and plants, along with ecosystem principles. The impact of his research is evidenced by over 200 refereed scientific publications and book chapters, including five papers in prestigious Journals of Nature and Science, and three in Proceedings of the National Academy of Sciences, and an invitational paper in Scientific American. His work has been highlighted extensively in the popular press, including CNN Science and Technology, BBC/ Discovery Channel, Business Week, National Public Radio and BBC Wildlife, Fortune Magazine, and NBC Today Show.

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