Abstract: A bacterial disease was found on summer squash basal stems in protected vegetable fields of 12 counties in Shandong Province from 2004 to 2006. One hundred and thirtyfive strains were isolated from 55 diseased plants. The pathogenicities of some strains showed that all these strains could cause the same symptoms as in the open field. The pathogen was identified as Erwinia carotovora subsp. carotovora based on the morphology, dyeing reaction, culture characteristics, physiological and biochemical tests.

Key words: Summer squash, Basal stem, Bacterial soft rot, Pathogenic identification, Erwinia carotovora subsp. carotovora