Weed Research

PAUL E. HATCHER is Associate Professor in Applied Ecology in the School of Biological Sciences at the University of Reading, working on perennial weed control and biological control of weeds and insects. He has been a member of the EWRS since 1993, and was Chair of the EWRS Biological Control working group for many years. He is Chair of the Editorial Board for the Wiley-Blackwell journal Weed Research, and a member of the Board of the EWRS. He is also a member of the DEFRA steering group on weed biological control. ROBERT J. FROUD-WILLIAMS was Senior Lecturer in Weed Science in the School of Biological Sciences at the University of Reading and has research interests in weed ecology, agri-environment and integrated weed management. During his career within the university he supervised more than forty postgraduate students. He has been a member of EWRS since 1980 and was elected Vice President in 2001 and President in 2003 in addition to his former role as National Representative. He has been a member of several external committees including BCPC Expert Weeds and for eighteen years was Chairman of the UK Weed Liaison Group representing publicly-funded weed science in the UK. He also was member of various committees including Defra Sustainable Arable Link, Association of Applied Biology Weeds and Agronomy Group, member of the advisory board for Aquatic Plant Management Committee and steering committee of the Arable Plants Group within Plantlife.

• List of Contributors xvPreface xix1 Weed Science Research: Past, Present and Future Perspectives 1Robert J. Froud]WilliamsIntroduction 1Factors Influencing the Weed Flora 2Succession 2Clean Seed 3Rotation 3Fallow 4Cultivation 5Straw Burning 5Soil Amelioration, Drainage and Fertiliser Use 5Nitrogen 6Herbicides 6Consequences of Changing Practices 9Changing Weed Floras 9Episodic Decline 13Weed Spatial Distribution 13History of Weed Science in the UK and Origins of the Weed Research Organisation 14Origins of the European Weed Research Society 17Weed Research (Journal): Origin of Papers and Discipline 18Changing Attitudes to Weeds 18Set]Aside and Agri]Environment 19Weeds, Climate and Invasive Aliens 20Future Directions (Quo Vadis?) 21Environmental Weed Management 21Evolutionary Genetics and the Role of Molecular Ecology 22Is there a Need for a Change of Emphasis? 22Conclusion 23Acknowledgements 24References 242 Descriptive and Mechanistic Models of Crop–Weed Competition 33Lammert Bastiaans and Jonathan StorkeyIntroduction 33Descriptive Models for Yield Loss Due to Weed Competition 34The Hyperbolic Yield Loss–Weed Density Curve 34Accounting for Differences in Relative Time of Emergence 36Other Factors Influencing Parameter i 39Management Aimed at Modifying Crop–Weed Competitive Relations 40A Quantitative Characterisation of Differences in Weed]Suppressive Ability of Crop Cultivars 45Mechanistic Models for Crop–Weed Competition 46Structure and Function of Process]Based Models for Crop–Weed Competition 46A First Application: Ideotyping of More Weed]Suppressive Cultivars 50A Second Application: Predicting the Impact of Climate Change on Weed Distribution 51Conclusion 55References 563 Approaches and Objectives of Arable Weed Species Mapping: Where Next? 61Hansjörg Krähmer and Paolo BàrberiWeed Species Mapping: Why? 61Scientific Literature: State of the Art 62Mapping Herbicide]resistant Biotypes 63Mapping Invasive Species 63Weed Species Mapping: Who? 65Weed Species Mapping: Where and What? 66Maps of Weeds in European Arable Crops 66Field]Level Mapping 71Weed Species Mapping: How? 72Geo]Referencing 72Timing of Assessment 74Sampling Parameters 74Documentation and Maps 74What to Conclude from Weed Mapping Data? 75Weed Mapping: Where to Go? 76Acknowledgements 80References 804 Seed Biology and Population Dynamics 85Kirsten S. Tørresen, Laila M. Karlsson and Jose Luis Gonzalez]AndujarIntroduction 85Seed Biology 86Seed Production and Dispersal 86Seed]Bank 88Germination and Dormancy 90Germination 90Dormancy 91Sprouting from Vegetative Plant Parts 96Predicting Seedling Emergence 97Empirical Models 97Mechanistic Models 97Challenges in Predicting Emergence 98Importance for Weed Control 99Population Dynamics 100Dynamics in Time and Space 100Modelling 100Non]Spatial Models 101Spatial Models 103Practical Applications in Weed Science 103Evaluation of Management Systems 103Decision Support Systems 104Challenges in Modelling Population Dynamics 104Future Prospects 104Conclusion 105Acknowledgements 106References 1065 Weeds and Biodiversity 115Bärbel Gerowitt, Paolo Bàrberi, Henri Darmency, Sandrine Petit, Jonathan Storkey and Paula WestermanIntroduction 115Arable Weeds in the Context of Biodiversity 116Functional Biodiversity 116Agronomic Services and Disservices Associated with Weeds 117Genetic Diversity in Weeds 117How to Measure Genetic Diversity 119At Which Scale Can Genetic Diversity Be Described? 120Why Is It Important to Understand Weed Genetic Diversity? 121Rare Weed Species as Objects of Conservation 122Drivers of Arable Weed Declines 123The Rare Weed Trait Syndrome 124Conserving Rare Weed Communities 124Weeds in Food Chains of Arable Systems 124Factors Influencing Seed]Based Food Webs in Agroecosystems 126Weed Seed Production 126Within]Season Temporal Variability 126Between]Season Temporal Variability 126Spatial Variability 127Seed Morphology and Chemistry 127Weed Diversity 127Current Status of Seed]Based Food Webs on Farms and Management Options 127Diversity of Weeds and Arable Management 129Site Conditions of Arable Fields Filter for Weed Communities 129Methods to Identify and Separate the Influence of Arable Site and Arable Management on Weed Diversity 130Arable Management Determines Weed Diversity 131Weed Diversity Versus Weed Abundance 131Diversity in Weeds Facilitates Management Options 132Diversity of Weeds in a Landscape Context 133The Landscape Context of Weeds 133Conducting Landscape]Scale Weed Studies 134Landscape Effects on Weed Biodiversity: Empirical Evidence 135Biodiversity of Weeds and Public Interest 136Field Margin Programmes 136Encouraging Weed Diversity in Farming 136Conclusions and Perspectives 137References 1386 Optimising Herbicide Performance 149Per KudskIntroduction 149Herbicide Classification 150Optimising Herbicide Performance: How to Study It 151Biotic Factors 154Weed Flora 154Weed Growth Stage 156Crop Competition 157Abiotic Factors 158Soil Texture 158Climatic Conditions 159Light 159Temperature 160Humidity 161Precipitation 162Soil moisture 163Wind 164Concluding Remarks 164Application Technique 165Adjuvants 166Mixtures with Other Herbicides 168Concluding Remarks and Future Challenges 170References 1727 Herbicide Resistance in Weeds 181Stephen MossHistorical Perspective 181What Is Herbicide Resistance? 182The Worldwide Occurrence of Resistant Weeds 183Herbicide Mode of Action and Risk of Resistance 185Resistance Mechanisms 188Target]Site Resistance 188PSII (Triazines) 189ALS Inhibitors 190ACCase Inhibitors 190Other Herbicide Classes 191Non]Target]Site Resistance 191Reduced Herbicide Uptake 193Reduced Herbicide Translocation 193Enhanced Herbicide Metabolism 194Evolution of Herbicide Resistance 194Initial Frequency of the Resistance Trait and Size of Weed Population 195Genetic Basis of Resistance 197Selection Pressure 199Frequency of Herbicide Use 199Persistence of the Herbicide and Pattern of Weed Emergence 199Intrinsic Activity of the Herbicide and Degree of Resistance Conferred by the Resistance Mechanism(s) 200Specificity of the Herbicide: Number of Species the Herbicide Controls 201Seed Bank in the Soil 201Resistance Risk 201Prevention and Management of Herbicide Resistance 203Detection of Resistance in the Field 203Integrated Weed Management 203Non]Chemical Control Methods 204Herbicidal Control 204Alternative Herbicides 204Mixtures, Sequences and Rotations 205Managing Resistance in Alopecurus Myosuroides (Black]grass): A Case Study 205Farmer Psychology: An Under]Recognised Component of Resistance Management 206Conclusion 209References 2098 Weed Biological Control 215Richard H. Shaw and Paul E. HatcherIntroduction 215Definitions of Weed Biocontrol 217Biocontrol of Weeds in European Extensive Agriculture 218Cirsium Arvense 219Rumex Species 221Biocontrol of Weeds in Intensive Agriculture 222Biocontrol of Non]native Weeds 224Ambrosia 228In Summary 230Combining Biocontrol with Other Weed Control Techniques 230Combining with Other Non]Chemical Control Methods 231Combination with Herbicides 232Arthropod Biocontrol Agents 232Fungal Biocontrol Agents 233Legislation, Responsibilities and Drivers 234Arthropods 234Fungi 235Conclusion 235References 2369 Non]Chemical Weed Management 245Bo Melander, Matt Liebman, Adam S. Davis, Eric R. Gallandt, Paolo Bàrberi, Anna]Camilla Moonen, Jesper Rasmussen, Rommie van der Weide and Francesco VidottoIntroduction 245Preventive and Cultural Weed Control 246Objectives, Principles and Practices 247Objective 1: Reduce Weed Density 247Objective 2: Reduce Damage Per Surviving Weed 248Objective 3: Prevent Undesirable Shifts in Weed Community Composition 249Current Adoption and Challenges 250Cover Crops and Mulches 250Mechanisms of Cover Crop–Weed Interactions 251Challenges for Research 252Mechanical Weed Control 253How It Works 256Shortcomings 257Challenges for Research 258Thermal Weed Control 259Thermal Weed Control in Practice 262Challenges for Research 263Conclusion 263References 26410 Invasive Plants 271Christian BohrenIntroduction 271Why Do Invasive Plants Symbolise such a Threat? 271Invasive Weeds and Human Health 271Ambrosia 272Giant Hogweed 273Weedy Crops, Super Weeds and Mimetic Weeds 274Invasive Aquatic Weeds 275Human Intervention 276Human Curiosity 276Reasons for Increased Occurrence of Invasive Weeds 276Responsibility 277Scientific Prioritisation 278Popular Prioritisation 278Implementation 279Facts Concerning Plant Invasion 280The Early Beginnings 280Changing Land Use and Fishery 281Rapid Adaptation 282Weeds, Invasives and Climate Change 282What Makes Plant Invaders so Successful? 283Can We Predict Plant Invasions? 284What Has Been Done so Far? 285Databases 285European Initiative 285European Food Safety Agency (EFSA) 288Euphresco 288SMARTER 288Role of the EWRS Invasive Plants Working Group 289Mission 289Working Group Activities 289Ponta Delgada, Azores, Portugal, 2006 289Osijek, Croatia, 2008 290Ascona, Switzerland, 2011 290Montpellier, France, 2014 290EPPO Trabzon 291NEOBIOTA 291Aquatic Weeds 291Definitions and Plant Lists 291Definitions 291Weed 292Invasive Plant 292Plant Invader 294Invasion Trajectory 294Invasive Species Lists 294Control Strategies for Invasive Weeds 294Biological Control Versus Conventional Control 294Learning to Control Invasions 298Social and Economic Aspects 300Anthriscus 300Japanese Knotweed 300Bracken 301Ambrosia 302Strategies 302Prevention 302Early Detection 302Rapid Response 302Pest Risk Assessment 303Species]Specific Control 303Conclusion 303References 30611 Parasitic Weeds 313Maurizio Vurro, Alejandro Pérez] de]Luque and Hanan EizenbergIntroduction 313Classification 315Orobanchaceae (Broomrape Family) 315Cuscuta 315Life]Cycle 316Broomrapes 316Dodder 317Distribution at the European Level, Host Range and Yield Losses 318Management Strategies 325Management and Control 325Biological Control 325Natural Products 328Strigolactones and Other Germination Stimulants 329Nanotechnological Approaches 332Genetic Resistance 334Defensive Mechanisms 335Novel Genetic Approaches 337Chemical Control of Broomrapes 337Herbicide]Resistant Crops for Broomrape Control 340Developing Models for Optimising Chemical Control of Root Parasitic Weeds 341Precision Agriculture 342Conclusion 346References 34612 Weed Management Systems in Vegetables 355Francesco Tei and Euro PannacciIntroduction 355Weed Flora 357Weed–Vegetable Crop Interactions 358Integrated Weed Management 365Preventive Measures 366Cultural Methods 366Crop Rotation 366Cover]crops 367Stale Seed]Bed Preparation 368Cultivar Selection 368Planting Method, Planting Pattern, Row Spacing and Crop Density 368Physical Weed Control 368Non]Living Mulches 369Solarisation 369Flaming 369Steaming 370Mechanical Weed Control 370Hand]Weeding 371Biological Weed Control 371Chemical Weed Control 371Conclusions and Perspectives 377References 38013 Perennial Weeds 389Paul E. HatcherIntroduction 389Perennating Structures 390Fragmentation, Nutrient Reserves and Regrowth 391Dormancy of Vegetative Structures 392Grassland Perennials 392Perennials in Organic Arable Systems 394Perennials of Southern European Agriculture 396Cyperus Species 397Sorghum Halepense 398Bracken 399Conclusion: Perennial Weeds in the Future 401Climate Change 401Reduced Tillage 402References 403Index 000