Herbicide Resistance and World Grains PDF

Preface

Weeds have been the bane of farmers since humanity changed from hunting and gathering to settled agriculture. Weeds compete directly with crops for space, nutrients, and light, and they are among the major limitations on crop yield. The discovery and use of selective herbicides that began with the auxinic herbicides in the late 1940s was one of the primary reasons for the spectacular increases in crop productivity over the past 50 years. Farmers throughout the major crop production areas of the world now depend on herbicides to manage weeds. However, evolution continues, and the selective pressure that herbicides exert on weed populations selects for rare resistant biotypes that can quickly proliferate and dominate the population. If a herbicide is used persistently the selection of resistance is inevitable. Australia is a model of what can happen with unbridled use of herbicides and the selection of herbicide-resistant populations.

Management of herbicide-resistant weed populations has received increasing attention following the initial selection and identification of triazine-resistant weeds 30 years ago in the United States. In the 1990s industry and academia made major efforts to develop practical, cost-effective guidelines that farmers could use to achieve integrated weed management with herbicides as a major, but not exclusive, tool.

Although there are several excellent books and numerous papers on herbicide resistance, there is no compilation of the latest information on resistance and its management in the major world grain crops. Both editors of this book have been intimately involved in practical herbicide-resistance management from academic and industrial perspectives. As a result, we feel that the agricultural community needs access to the information on herbicide-resistance management from experts who have been dealing with this problem.

Farmers will adopt herbicide-resistance management techniques and tools if they accept the economic sense of these practices. Farming must be profitable in order for farmers to remain in business and resistance management has both short- and long-term costs. It is important to understand these costs and how they impact the implementation of resistance management. If resistance management is not economically acceptable, the recommendations for resistance management will not be adopted. Hence, we include chapters on resistance management in major world grain crops, the economic impact of resistance management, and the latest information on new models for comparing different resistance-management strategies. We also include regulatory affairs because major changes in the regulation of herbicides now include resistance management as a key component in the registration of new herbicidal products.

The chapter authors summarize the current state of herbicide resistance in major grain crops and present the latest information on how to manage resistant weed populations. They also indicate unanswered questions and future research needs. This information can be the springboard to new research and new solutions.

An overriding theme of this book is the need for integrated weed management. As one of the editors has frequently stated, herbicide resistance has been a primary driver for the implementation of integrated weed management in Australia. This is the future of weed management. Herbicides have played a vital role in increasing crop production throughout the world, but complete dependence on herbicides for weed management is nonsustainable. Herbicides must be part of an integrated system. Herbicide-resistance problems demonstrate the weakness of over-reliance on a single weed management tool. The editors hope that this book will help lead the way to true integrated weed management, in which herbicides play an integral, but not exclusive, role.