There is growing concern among scientists, farmers and the general public that pesticides are being applied ever more widely but with less and less discretion. This book brings together a range of experts to discuss how crop protection chemicals can be used more rationally, so as to maximise benefits in yield and quality while minimising environmental and economic costs. The book is based on the ninth Long Ashton Symposium and is organised into four sections. The first, environment, examines to what extent current pesticide use is affecting the environment and human welfare, and what changes in practice are justified. The second, application, assesses progress in performance and safety in the use of pesticides, while the next section, resistance, looks at problems and shortcomings arising from the appearance of resistant strains of pests, and considers strategies for surmounting these difficulties. The final section, forecast and pest management, asks whether existing methods of assessing risks are acceptable and seeks ways of rending decision making in crop protection more rational.