Technology Description: The invention is a biologically pure culture of one strain of the bacterium, Erwinia herbicola, which is an effective biological control against the disease-causing bacterium, Erwinia amylovora. The pathogenic bacterium causes fire blight, a destructive disease of pear and apple trees. Disease incidence varies from one growing season to another depending on weather, causing severe product losses in some years. In addition, the effect of fire blight can have long-term because of the loss of productive fruit trees. The invention is a way to biologically control fire blight using naturally occurring microorganisms that inhibit or out compete E. amylovora on flower tissues, the primary means of infection. Antibiotic treatments are currently used by growers to combat fire blight disease; however, this practice has become less effective because of the development of resistance in E. amylovora. The invention could reduce grower dependency on antibiotic treatments, and at the same time, help maintain antibiotic effectiveness by minimizing the chance of resistance. Over the long term, use of the invention would result in fewer losses due to fire blight and possibly a reduction in the cost of managing this potentially devastating disease. Reference: Please refer to Patent Number 5,919,446, which issued on July 6, 1999. Inventor: Paul Lawrence Pusey Physiology and Pathology of  Tree Fruits Research Wenatchee, WA 98801 (509) 664-2280 / Fax: (509) 664-2287 pusey@tfrl.ars.usda.gov