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Poster: Diseases of Plants: New & Emerging Diseases


Red rust of bromeliads caused by a parasitic alga in Florida
G. Sanahuja (1), P. Lopez (1), A. Palmateer (1) (1) University of Florida, U.S.A.

Cephaleuros is a genus of plant parasitic thalloid green algae containing at least two species C. virescens and C. parasiticus that are reported to cause disease on ornamental plants. Florida has 165 plant species belonging to 53 families that have been reported as hosts of Cephaleuros. Recent outbreaks of a “red rust” disease affecting bromeliads in production nurseries and landscapes led to an investigation of the causal agent, which was determined to be a Cephaleuros species. Morphological characteristics from Cephaleuros isolates recovered from Neoregelia hybrids match with isolates of C. parasiticus collected from leaves of Psidium guajava (guava). Molecular analyses were performed from 18S ribosomal RNA and ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) genes. Pathogenicity tests were conducted using Cephaleuros isolates collected from leaves of Neoregelia hybrids and isolates of C. parasiticus from guava. Both produced symptoms consistent with those originally described as “red rust” on Neoregelia hybrids and the causal agent of red rust on Neoregelia hybrids provisionally will be Cephaleuros parasiticus.