Non-conspecificity of Cylindrocladium quinqueseptatum and Calonectria quinqueseptata based on a beta-tubulin gene phylogeny and morphology

Cylindrocladium quinqueseptatum Boedijn & Reitsma was originally described from leaf spots of Hibiscus sabdariffa L. from Indonesia. This fungus infec ts many host plants in Southeast Asia and causes severe leaf blight disease of eucalypts. Calonectria quinqueseptata Figueiredo & Namek., which was de scribed from leaf spots on Annona squamosa L. from Brazil, has been regarde d as the teleomorph of Cy. quinqueseptatum. Based on morphology and on the phylogeny derived from the DNA sequence of a beta-tubulin gene portion span ning several phylogenetically informative introns, the two respective ex-ty pe cultures are shown to be distinct species. Furthermore, Calonectria rete audii (Bugn.) C. Booth (anamorph Cy. reteaudii (Bugn.) Boesew.), which was described on Smithia bequaertii De Wild. from Vietnam, is shown to be morph ologically identical to a comprehensive selection of isolates of Cy. quinqu eseptatum from Southeast Asia, Australia, and Madagascar. As Cy. reteaudii represents an older name for Cy. quinqueseptatum, we suggest that the fungu s causing widespread damage on eucalypts and other hosts in the above regio ns be referred to as Cy. reteaudii. Calonectria quinqueseptata should be re tained for the fungus that thus far has been found only in Brazil.