Leaf Spot and Blight of Asplenium nidus Caused by Pseudomonas gladioli. A. R. Chase, Associate Professor of Plant Pathology, University of Florida, IFAS, Agricultural Research Center, Apopka 32703. J. W. Miller, Plant Pathologist, Department of Agriculture and Consumer Services, Division of Plant Industry, Gainesville, FL 32602; and J. B. Jones, Assistant Professor of Plant Pathology, University of Florida, IFAS, Agricultural Research and Education Center, Bradenton 33508. Plant Dis. 68:344-347. Accepted for publication 27 December 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-344.

A leaf spot and blight of Asplenium nidus (bird’s nest fern) caused extensive losses in many Florida nurseries. A nonfluorescent pseudomonad was isolated consistently from affected ferns. Comparisons of this organism with Pseudomonas asplenii, a fluorescent pseudomonad causing similar symptoms on the same host, indicated differences in the host ranges of the two organisms but not in virulence on bird’s nest fern. P. asplenii was highly virulent on the original host only. It caused slight symptoms on five of 10 other ferns tested. The nonfluorescent pseudomonad was highly virulent on four of the 11 ferns tested and avirulent on only two varieties of ferns. On the basis of biochemical and nutritional tests, the nonfluorescent pseudomonad was identified as P. gladioli, a pathogen of gladiolus, P. gladioli was pathogenic on bird’s nest fern and the fern pathogen was pathogenic on gladiolus.

Keyword(s): Adiantum, Davallia, foliage plants, Pelleae, Platycerium, Pteris.