ABSTRACT
This chapter, discuses disease under the categories fungi, bacteria and viruses. A range of these problems are presented, showing relevant symptoms, life-cycle details that explain their success and a description of a range of control measures available to the horticulturist. Emphasis is given in this chapter to a broad integrated choice of control measures. A plant disease is an unhealthy condition in a plant caused by a fungus, bacterium or virus. The damp climate of Britain and Ireland favours a wide range of plant diseases. The great variety of plant species leads to further opportunities for infections. The earliest infections are likely to occur in the upper parts of the leaf canopy, infections often being observed first in taller trees and subsequently on shrubs in the under-story. As the weather becomes cooler in autumn, possibly after an oospore infection, the organism produces thick-walled chlamydospores.
