Pusey, P. L., Stockwell, V. O., and Mazzola, M. 2009. Epiphytic bacteria and yeasts on apple blossoms and their potential as antagonists of Erwinia amylovora. Phytopathology 99:571-581. Apple blossoms were sampled for indigenous epiphytic populations of culturable microorganisms during different stages of bloom at two locations in central Washington State and one site in Corvallis, OR. Frequenc...

Virulent E(9) and avirulent E(8) strains of Erwinia amylovora were shown by means of light, transmission, and scanning microscopy to be, respectively, encapsulated and unencapsulated. Difficulty was encountered in stabilizing the fibrillar-appearing capsular extracellular polysaccharide. We suggest that the ephemeral nature of extracellular polysaccharide is due to the collapse of its extended ...

Extracts prepared from apple seeds contain a factor (AF) capable of agglutinating cells of Erwinia amylovora. In drop agglutination tests, AF is more active in agglutinating an avirulent, acapsular strain of E. amylovora than a virulent, capsular strain. AF precipitates in agar plates with a receptor derived from boiled cells of avirulent acapsular strain and, therefore, can be located during f...

Abstract Fire blight is a devastating disease of apple, pear and quince caused by the Gram-negative bacterium Erwinia amylovora . As antibiotics are not allowed against fire in Switzerland, optimization alternative plant protection strategies required. In this context, tolerant cultivars become higher importance to control disease. A product efficacy trial with susceptible cultivar ‘Gala Galaxy...