Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2012
Publication Date: July 1, 2012
Citation: Crouch, J. 2012. Colletotrichum fungal pathogens and symbionts of ornamental nursery and landscape plants. Phytopathology. 102(7):S4.26-S4.27. Technical Abstract: Fungi in the ascomycete genus Colletotrichum are ranked by the plant pathology community as one of the ten most economically and scientifically important fungal phytopathogens. Major losses due to Colletotrichum are experienced in almost every crop worldwide, including nursery and landscape plants cultivated for ornamental uses. Accurate diagnosis of Colletotrichum associated with ornamentals and other crops has long been problematic due to unresolved taxonomic boundaries in the genus. In general, Colletotrichum associated with ornamental crops are poorly studied, and difficulties in diagnosis are confounded by the fact that there are few good morphological characters capable of precisely discriminating between species. In the present study, Colletotrichum associated with broadleaf evergreen ornamental shrubs and groundcovers (e.g. rhododendron, azalea, boxwood, holly, English ivy, liriope) were surveyed from the eastern United States. Broadleaf evergreens are the largest sector of the U.S. nursery industry, generating >$793 billion annually. Multilocus DNA sequence analysis was used to genotype pathogenic and asymptomatic symbiotic Colletotrichum isolated from collected foliar tissue. Phylogenetic analyses were used to identify species associated with these plants, including both known species and Colletotrichum that have previously gone undiagnosed. These data will provide baseline information useful for diagnosis of Colletotrichum diseases of ornamentals.