Abstract
This chapter presents the description of the species Erwinia amylovora (causal agent of fire blight) as given by taxonomists. Such a description is necessarily general, gathering the common traits of individuals of the species. It provides a means to separate this species from other groups of organisms and gives a minimal picture of what is generally recognized by microbiologists and phytopathologists, as the species E. amylovora. Additional information on the cultural and morphological characteristics, physiology and nutrition, serology and phage sensitivity of E. amylovora are also presented.