Matt Liebman, Charles L. Mohler, and Charles P. Staver
Cambridge University Press, 2001, 532 pp.
Price: $120
ISBN 0-521-56068-3 (hardbound)

The words "ecological management" and "agricultural weeds" seldom appear in the same phrase, let alone as the title of a book. This book changes that and does so credibly. These three authors explore the reasons why ecological management of agricultural weeds should be at the forefront of weed science in the future. Many books about weed management focus on herbicides and their use, whereas the intent of this book is to establish ecological principles as the basis for sound and successful weed management. This is a synthetic work, rather than a series of papers or chapters by invited authors, and it reads very well. The book’s eleven chapters flow smoothly, from setting the stage in the first chapter for why we should consider alternatives to chemicals to manage weeds, to a philosophical perspective on integration of ecology into overall farm management.

Herbicides dominated the weed management in the last half of the 20th century. Indeed, mechanization of agriculture codeveloped with pesticide (not just herbicide) technology, shaping agriculture as it now is practiced. But the authors forecast changes in how weeds are managed, for several reasons. By the late 1990s, at least 145 species of weeds were found to be resistant to herbicides; that resistance occurred in at least 16 classes of herbicides. The appearance of herbicide resistance in weeds is comparable to the evolution of insecticide resistance in arthropods. Coupled with decreased development of new herbicides and herbicide classes, there will be fewer chemical arrows in the weed management quiver in the future. Herbicides also move from application sites to enter surface and groundwater and affect nontarget species, including humans. At the same time, the emergence of transgenic, herbicide-tolerant crop plants is leading to an increased reliance on a narrower spectrum of herbicides.

Chemical farming is often touted because of its labor savings and economic returns to the grower. The authors point out, however, that those labor and cost savings accrue off-farm. Much of the economic benefit from chemical use goes to suppliers. Studies show that ecological weed management can produce returns that can stay on the farm.

The underlying philosophical theme of the book is broadening the approach to weed management. Shifting from linear, species-specific control goals to an understanding of the webs among weed and crop species and their effects on farming practices is critical to changing how we view and manage weeds. The authors emphasize incorporating multiple stressors against weeds, whether through chemical and mechanical methods, to integrating biological control agents and competition from the crop itself. Interesting idea: Enhance crops for their competitive abilities to suppress weeds and not just produce a high yield. These guys are onto something. They also devote a chapter to weed evolution and community structure. Recognizing that growers make decisions to manage weeds in the short-term, they discuss the importance of altering and managing weed communities—not eliminating weeds—and offer strategies for achieving longer term goals.

Their presentation of biological weed control is balanced in the way it fits into the other topics. Unusual is the emphasis they place on conservation of extant weed biological control agents to impose stress on weeds. This topic is often overlooked or criticized because it is not sufficient to control weeds predictably or to a level that requires no other inputs. The authors argue that it is important to conserve natural enemies, because they add stress against the weeds, rather than do the job alone. They prescribe an integrated approach in which biological control fits with the stresses from other sources. They place the importance of host specificity of herbivorous natural enemies into context and also recognize the difficulty of the specificity of weed biological control because agents do not target the entire suite of weeds in a crop habitat.

Why should this book be of interest to entomologists? The authors’ philosophical approach transcends weed science and applies across taxonomic boundaries. The need to incorporate multiple approaches is something entomologists have long known; we call it integrated pest management (IPM). Yet, the arguments made by these three authors remind us that we try to impose IPM onto a simplified agricultural habitat with too little regard for other problems. When we try to win the battle of managing a single insect, weed or disease, we often lose the war by making the agroecosystem and its economic outputs less sustainable.

This text would be appropriate for an advanced course or seminar; it is an important piece from which to draw for the next generation of all crop protection professionals, not just weed scientists. Furthermore, the approaches presented here should be the basis for future weed science textbooks. I laud the authors for their balanced—not shrill—call for a philosophical shift in how we view and sustainably manage pests in agroecosystems.

Robert N. Wiedenmann
Illinois Natural History Survey
Champaign, IL 61820
American Entomologist
Vol. 49, No.1, Spring 2003