Introduction

Weeds are not different from other plants that compete for survival. However, weeds are considered as plants growing 'out of place' or where they are not intentionally planted, and hence undesirable for human activities. Weeds are also a huge menace to rangelands, pastures, parks, and recreation areas. If left unchecked in these regions, they affect livestock production, reduce property values, create safety hazards, and destroy ecosystems. Although the study of weeds has been a part of agricultural education for a long time, weed science emerged as a discipline and came into limelight upon introduction of herbicides for weed management in the 1950s. This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book aims to integrate three primary areas of weed science research; weed biology, physiology, and molecular biology.