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.

This book presents the most up-to-date and comprehensive guide to the current and potential future state of weed science and research. Weeds have a huge effect on the world by reducing crop yield and quality, delaying or interfering with harvesting, interfering with animal feeding (including poisoning), reducing animal health and preventing water flow. They are common across the world and cost billions of dollars' worth of crop losses year on year, as well as billions of dollars in the annual expense of controlling them. An understanding of weeds is vital to their proper management and control, without which the reduction in crop yields that they would cause could lead to mass starvation across the globe.
Topics covered include weed biology and ecology, control of weeds and particular issues faced in their control. Authored and edited by internationally renowned scientists in the field all of whom are actively involved in European Weed Research Society working groups, this succinct overview covers all the relevant aspects of the science of weeds. Weed Research: Expanding Horizons is the perfect resource for botanists, horticultural scientists, agronomists, weed scientists, plant protection specialists and agrochemical company personnel.

List of Contributors xv
Preface xix
1 Weed Science Research: Past, Present and Future Perspectives 1
Robert J. Froud?]Williams
Introduction 1
Factors Influencing the Weed Flora 2
Succession 2
Clean Seed 3
Rotation 3
Fallow 4
Cultivation 5
Straw Burning 5
Soil Amelioration, Drainage and Fertiliser Use 5
Nitrogen 6
Herbicides 6
Consequences of Changing Practices 9
Changing Weed Floras 9
Episodic Decline 13
Weed Spatial Distribution 13
History of Weed Science in the UK and Origins of the Weed Research Organisation 14
Origins of the European Weed Research Society 17
Weed Research (Journal): Origin of Papers and Discipline 18
Changing Attitudes to Weeds 18
Set?]Aside and Agri?]Environment 19
Weeds, Climate and Invasive Aliens 20
Future Directions (Quo Vadis?) 21
Environmental Weed Management 21
Evolutionary Genetics and the Role of Molecular Ecology 22
Is there a Need for a Change of Emphasis? 22
Conclusion 23
Acknowledgements 24
References 24
2 Descriptive and Mechanistic Models of Crop-Weed Competition 33
Lammert Bastiaans and Jonathan Storkey
Introduction 33
Descriptive Models for Yield Loss Due to Weed Competition 34
The Hyperbolic Yield Loss-Weed Density Curve 34
Accounting for Differences in Relative Time of Emergence 36
Other Factors Influencing Parameter i 39
Management Aimed at Modifying Crop-Weed Competitive Relations 40
A Quantitative Characterisation of Differences in Weed?]Suppressive Ability of Crop Cultivars 45
Mechanistic Models for Crop-Weed Competition 46
Structure and Function of Process?]Based Models for Crop-Weed Competition 46
A First Application: Ideotyping of More Weed?]Suppressive Cultivars 50
A Second Application: Predicting the Impact of Climate Change on Weed Distribution 51
Conclusion 55
References 56
3 Approaches and Objectives of Arable Weed Species Mapping: Where Next? 61
Hansjörg Krähmer and Paolo Bàrberi
Weed Species Mapping: Why? 61
Scientific Literature: State of the Art 62
Mapping Herbicide?]resistant Biotypes 63
Mapping Invasive Species 63
Weed Species Mapping: Who? 65
Weed Species Mapping: Where and What? 66
Maps of Weeds in European Arable Crops 66
Field?]Level Mapping 71
Weed Species Mapping: How? 72
Geo?]Referencing 72
Timing of Assessment 74
Sampling Parameters 74
Documentation and Maps 74
What to Conclude from Weed Mapping Data? 75
Weed Mapping: Where to Go? 76
Acknowledgements 80
References 80
4 Seed Biology and Population Dynamics 85
Kirsten S. Tørresen, Laila M. Karlsson and Jose Luis Gonzalez?]Andujar
Introduction 85
Seed Biology 86
Seed Production and Dispersal 86
Seed?]Bank 88
Germination and Dormancy 90
Germination 90
Dormancy 91
Sprouting from Vegetative Plant Parts 96
Predicting Seedling Emergence 97
Empirical Models 97
Mechanistic Models 97
Challenges in Predicting Emergence 98
Importance for Weed Control 99
Population Dynamics 100
Dynamics in Time and Space 100
Modelling 100
Non?]Spatial Models 101
Spatial Models 103
Practical Applications in Weed Science 103
Evaluation of Management Systems 103
Decision Support Systems 104
Challenges in Modelling Population Dynamics 104
Future Prospects 104
Conclusion 105
Acknowledgements 106
References 106
5 Weeds and Biodiversity 115
Bärbel Gerowitt, Paolo Bàrberi, Henri Darmency, Sandrine Petit, Jonathan Storkey and Paula Westerman
Introduction 115
Arable Weeds in the Context of Biodiversity 116
Functional Biodiversity 116
Agronomic Services and Disservices Associated with Weeds 117
Genetic Diversity in Weeds 117
How to Measure Genetic Diversity 119
At Which Scale Can Genetic Diversity Be Described? 120
Why Is It Important to Understand Weed Genetic Diversity? 121
Rare Weed Species as Objects of Conservation 122
Drivers of Arable Weed Declines 123
The Rare Weed Trait Syndrome 124
Conserving Rare Weed Communities 124
Weeds in Food Chains of Arable Systems 124
Factors Influencing Seed?]Based Food Webs in Agroecosystems 126
Weed Seed Production 126
Within?]Season Temporal Variability 126
Between?]Season Temporal Variability 126
Spatial Variability 127
Seed Morphology and Chemistry 127
Weed Diversity 127
Current Status of Seed?]Based Food Webs on Farms and Management Options 127
Diversity of Weeds and Arable Management 129
Site Conditions of Arable Fields Filter for Weed Communities 129
Methods to Identify and Separate the Influence of Arable Site and Arable Management on Weed Diversity 130
Arable Management Determines Weed Diversity 131
Weed Diversity Versus Weed Abundance 131
Diversity in Weeds Facilitates Management Options 132
Diversity of Weeds in a Landscape Context 133
The Landscape Context of Weeds 133
Conducting Landscape?]Scale Weed Studies 134
Landscape Effects on Weed Biodiversity: Empirical Evidence 135
Biodiversity of Weeds and Public Interest 136
Field Margin Programmes 136
Encouraging Weed Diversity in Farming 136
Conclusions and Perspectives 137
References 138
6 Optimising Herbicide Performance 149
Per Kudsk
Introduction 149
Herbicide Classification 150
Optimising Herbicide Performance: How to Study It 151
Biotic Factors 154
Weed Flora 154
Weed Growth Stage 156
Crop Competition 157
Abiotic Factors 158
Soil Texture 158
Climatic Conditions 159
Light 159
Temperature 160
Humidity 161
Precipitation 162
Soil moisture 163
Wind 164
Concluding Remarks 164
Application Technique 165
Adjuvants 166
Mixtures with Other Herbicides 168
Concluding Remarks and Future Challenges 170
References 172
7 Herbicide Resistance in Weeds 181
Stephen Moss
Historical Perspective 181
What Is Herbicide Resistance? 182
The Worldwide Occurrence of Resistant Weeds 183
Herbicide Mode of Action and Risk of Resistance 185
Resistance Mechanisms 188
Target?]Site Resistance 188
PSII (Triazines) 189
ALS Inhibitors 190
ACCase Inhibitors 190
Other Herbicide Classes 191
Non?]Target?]Site Resistance 191
Reduced Herbicide Uptake 193
Reduced Herbicide Translocation 193
Enhanced Herbicide Metabolism 194
Evolution of Herbicide Resistance 194
Initial Frequency of the Resistance Trait and Size of Weed Population 195
Genetic Basis of Resistance 197
Selection Pressure 199
Frequency of Herbicide Use 199
Persistence of the Herbicide and Pattern of Weed Emergence 199
Intrinsic Activity of the Herbicide and Degree of Resistance Conferred by the Resistance Mechanism(s) 200
Specificity of the Herbicide: Number of Species the Herbicide Controls 201
Seed Bank in the Soil 201
Resistance Risk 201
Prevention and Management of Herbicide Resistance 203
Detection of Resistance in the Field 203
Integrated Weed Management 203
Non?]Chemical Control Methods 204
Herbicidal Control 204
Alternative Herbicides 204
Mixtures, Sequences and Rotations 205
Managing Resistance in Alopecurus Myosuroides (Black?]grass): A Case Study 205
Farmer Psychology: An Under?]Recognised Component of Resistance Management 206
Conclusion 209
References 209
8 Weed Biological Control 215
Richard H. Shaw and Paul E. Hatcher
Introduction 215
Definitions of Weed Biocontrol 217
Biocontrol of Weeds in European Extensive Agriculture 218
Cirsium Arvense 219
Rumex Species 221
Biocontrol of Weeds in Intensive Agriculture 222
Biocontrol of Non?]native Weeds 224
Ambrosia 228
In Summary 230
Combining Biocontrol with Other Weed Control Techniques 230
Combining with Other Non?]Chemical Control Methods 231
Combination with Herbicides 232
Arthropod Biocontrol Agents 232
Fungal Biocontrol Agents 233
Legislation, Responsibilities and Drivers 234
Arthropods 234
Fungi 235
Conclusion 235
References 236
9 Non?]Chemical Weed Management 245
Bo Melander, Matt Liebman, Adam S. Davis, Eric R. Gallandt, Paolo Bàrberi, Anna?]Camilla Moonen, Jesper Rasmussen, Rommie van der Weide and Francesco Vidotto
Introduction 245
Preventive and Cultural Weed Control 246
Objectives, Principles and Practices 247
Objective 1: Reduce Weed Density 247
Objective 2: Reduce Damage Per Surviving Weed 248
Objective 3: Prevent Undesirable Shifts in Weed Community Composition 249
Current Adoption and Challenges 250
Cover Crops and Mulches 250
Mechanisms of Cover Crop-Weed Interactions 251
Challenges for Research 252
Mechanical Weed Control 253
How It Works 256
Shortcomings 257
Challenges for Research 258
Thermal Weed Control 259
Thermal Weed Control in Practice 262
Challenges for Research 263
Conclusion 263
References 264
10 Invasive Plants 271
Christian Bohren
Introduction 271
Why Do Invasive Plants Symbolise such a Threat? 271
Invasive Weeds and Human Health 271
Ambrosia 272
Giant Hogweed 273
Weedy Crops, Super Weeds and Mimetic Weeds 274
Invasive Aquatic Weeds 275
Human Intervention 276
Human Curiosity 276
Reasons for Increased Occurrence of Invasive Weeds 276
Responsibility 277
Scientific Prioritisation 278
Popular Prioritisation 278
Implementation 279
Facts Concerning Plant Invasion 280
The Early Beginnings 280
Changing Land Use and Fishery 281
Rapid Adaptation 282
Weeds, Invasives and Climate Change 282
What Makes Plant Invaders so Successful? 283
Can We Predict Plant Invasions? 284
What Has Been Done so Far? 285
Databases 285
European Initiative 285
European Food Safety Agency (EFSA) 288
Euphresco 288
SMARTER 288
Role of the EWRS Invasive Plants Working Group 289
Mission 289
Working Group Activities 289
Ponta Delgada, Azores, Portugal, 2006 289
Osijek, Croatia, 2008 290
Ascona, Switzerland, 2011 290
Montpellier, France, 2014 290
EPPO Trabzon 291
NEOBIOTA 291
Aquatic Weeds 291
Definitions and Plant Lists 291
Definitions 291
Weed 292
Invasive Plant 292
Plant Invader 294
Invasion Trajectory 294
Invasive Species Lists 294
Control Strategies for Invasive Weeds 294
Biological Control Versus Conventional Control 294
Learning to Control Invasions 298
Social and Economic Aspects 300
Anthriscus 300
Japanese Knotweed 300
Bracken 301
Ambrosia 302
Strategies 302
Prevention 302
Early Detection 302
Rapid Response 302
Pest Risk Assessment 303
Species?]Specific Control 303
Conclusion 303
References 306
11 Parasitic Weeds 313
Maurizio Vurro, Alejandro Pérez?] de?]Luque and Hanan Eizenberg
Introduction 313
Classification 315
Orobanchaceae (Broomrape Family) 315
Cuscuta 315
Life?]Cycle 316
Broomrapes 316
Dodder 317
Distribution at the European Level, Host Range and Yield Losses 318
Management Strategies 325
Management and Control 325
Biological Control 325
Natural Products 328
Strigolactones and Other Germination Stimulants 329
Nanotechnological Approaches 332
Genetic Resistance 334
Defensive Mechanisms 335
Novel Genetic Approaches 337
Chemical Control of Broomrapes 337
Herbicide?]Resistant Crops for Broomrape Control 340
Developing Models for Optimising Chemical Control of Root Parasitic Weeds 341
Precision Agriculture 342
Conclusion 346
References 346
12 Weed Management Systems in Vegetables 355
Francesco Tei and Euro Pannacci
Introduction 355
Weed Flora 357
Weed-Vegetable Crop Interactions 358
Integrated Weed Management 365
Preventive Measures 366
Cultural Methods 366
Crop Rotation 366
Cover?]crops 367
Stale Seed?]Bed Preparation 368
Cultivar Selection 368
Planting Method, Planting Pattern, Row Spacing and Crop Density 368
Physical Weed Control 368
Non?]Living Mulches 369
Solarisation 369
Flaming 369
Steaming 370
Mechanical Weed Control 370
Hand?]Weeding 371
Biological Weed Control 371
Chemical Weed Control 371
Conclusions and Perspectives 377
References 380
13 Perennial Weeds 389
Paul E. Hatcher
Introduction 389
Perennating Structures 390
Fragmentation, Nutrient Reserves and Regrowth 391
Dormancy of Vegetative Structures 392
Grassland Perennials 392
Perennials in Organic Arable Systems 394
Perennials of Southern European Agriculture 396
Cyperus Species 397
Sorghum Halepense 398
Bracken 399
Conclusion: Perennial Weeds in the Future 401
Climate Change 401
Reduced Tillage 402
References 403
Index 000