Evaluation of Likelihood of Co-Occurrence ofErwinia amylovorawith Mature Fruit of Winter Pear

Todd N. Temple, Virginia O. Stockwell, P. Lawrence Pusey, Kenneth B. Johnson
2007 Phytopathology  
Temple, T. N., Stockwell, V. O., Pusey, P. L., and Johnson, K. B. 2007. Evaluation of likelihood of co-occurrence of Erwinia amylovora with mature fruit of winter pear. Phytopathology 97:1263-1273. Phytosanitary concerns about fire blight prohibit export of U.S.-grown pears to some countries without this disease. To examine these concerns, we evaluated the potential for co-occurrence of Erwinia amylovora with mature, symptomless winter pear fruit by inoculation experiments and by survey of
more » ... rcial orchards. Immature pear and apple fruit were inoculated in orchards with E. amylovora strain 153N as resuspended lyophilized cells or as ooze from diseased tissues. Regardless of inoculum source, population size of Ea153N on fruit declined by an order of magnitude every 3 to 4 days during the first 2 weeks after inoculation; at 56 days after inoculation, Ea153N was not detected, except on 1 of 450 fruit with 4 colony forming units (CFU). After inoculation of flowers, calyx-end survival of Ea153N on pear and apple fruit declined from high populations at petal fall to a few cells at harvest, with no detection of the pathogen after a 7-week cold storage. Migration of Ea153N into symp-
doi:10.1094/phyto-97-10-1263 pmid:18943684 fatcat:3pt27fw5ave3totvgr3w3a53a4