Introduction

Surveys of disease incidence and severity have been carried out for important crops in many parts of the world. For example, the comprehensive surveys undertaken under the auspices of the Home Grown Cereals Authority (HGCA) record the incidence of diseases in the principal arable crops in the UK. However, it has often proved difficult to determine accurately in strict monetary terms losses due to attack by individual pathogens. Disease levels often vary greatly from season to season. Crop losses may result from attacks by more than one pathogen. Furthermore, crop growth is affected by other factors such as climate, soil type, and environmental and cultural conditions, and these factors frequently interact.

Consideration is given in this chapter to the aetiology and current importance of diseases of the principal arable crops and selected diseases of top fruit and protected crops grown in the UK. Features of the life cycle of pathogens that are particularly relevant to the development of control measures are emphasised.