VIEW ARTICLE

Ecology and Epidemiology

New Medium for Detecting Erwinia amylovora and Its Use in Epidemiological Studies. C. Ishimaru, Graduate assistant, Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824-1312; E. J. Klos, professor, Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824-1312. Phytopathology 74:1342-1345. Accepted for publication 11 June 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/Phyto-74-1342.

A medium, CCT, was developed that distinguishes Erwinia amylovora from E. herbicola on the basis of colony morphology. Accuracy is such that one colony-forming unit (cfu) of E. amylovora per milliliter can be detected in the presence of 10⁴ cfu of E. herbicola per milliliter on CCT. Forty-five of 48 virulent strains of E. amylovora tested had similar colony morphology on CCT, while numerous other bacterial species have dissimilar morphologies. CCT was successfully used to detect E. amylovora in apple blossoms, buds, and cankers prior to development of fire blight symptoms.