VIEW ARTICLE

Etiology

Bacterial Blight Incited in Parsnip by Pseudomonas marginalis and Pseudomonas viridiflava. J. E. Hunter, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456; J. A. Cigna, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. Phytopathology 71:1238-1241. Accepted for publication 16 March 1981. Copyright 1981 The American Phytopathological Society. DOI: 10.1094/Phyto-71-1238.

Pseudomonas marginalis and P. viridiflava were isolated from soft rot lesions on parsnip petioles collected from a field in eastern New York in 1978 and 1979. In sections of the field, the disease was so severe that the tops of many plants were destroyed, making mechanical harvesting of the roots impossible. In 1979, P. marginalis was recovered from diseased petioles collected from two locations in Massachusetts. It was the only pathogen recovered from naturally infected roots in any location. Both species caused soft rotting of inoculated petioles, but only P. marginalis moved into the roots and caused a hard brown rot. P. viridiflava, however, was recovered from symptomless roots of plants that had been inoculated at the crown. Only P. viridiflava was recovered from two lots of seeds and these isolates were pathogenic to parsnip petioles. The validity of P. pastinacae, a species described from parsnip in New York in 1960, is questioned.