CSIRO PUBLISHING www.publish.csiro.au/journals/apdn Australasian Plant Disease Notes, 2009, 4,62–63

Two new hosts, Epidendrum secundum and Epidendrum xanthinum, for the orchid Sphenospora kevorkianii (Raveneliaceae) in Brazil

O. L. PereiraA,B and M. SilvaA

ADepartamento de Fitopatologia, Universidade Federal de Vicosa,¸ 36570-000 Vicosa,¸ M.G., Brazil. BCorresponding author. Email: [email protected]

Abstract. The rust Sphenospora kevorkianii, is reported on two new orchid hosts, Epidendrum secundum and Epidendrum xanthinum, in the state of Minas Gerais, Brazil.

Epidendrum secundum is an orchid with either an epiphytical or In 2006, an exploratory project to survey and describe the terrestrial habitat, characteristic of the Brazilian campos rupestres phytopathogenic fungi associated with the family Orchidaceae (montane grassland savanna). Epidendrum xanthinum is an in the state of Minas Gerais, Brazil was initiated (Silva and Pereira epiphytic characteristic of the Brazilian Atlantic 2007, 2008; Silva et al. 2008). During this survey in the campos rainforest. Both species are propagated by many Brazilian rupestres of Carrancas city and on a commercial orchid nursery in orchid growers, especially E. secundum for its cut flowers. Araponga city, samples of the rust-infected orchids E. secundum

(a) (a)

(b) (b)

Fig. 1. Rust symptoms on adaxial and abaxial leaf surfaces of Epidendrum Fig. 2. Rust symptoms on adaxial and abaxial leaf surfaces of Epidendrum secundum (VIC 30693). xanthinum (VIC 30694).

Australasian Plant Pathology Society 2009 10.1071/DN09026 1833-928X/09/010062 Orchid rust in Brazil Australasian Plant Disease Notes 63 and E. xanthinum were collected. Leaf lesions were yellowish Sphenospora kevorkianii is a rust which was first to orange-brown, covered in powdery spore masses and coloured reported from the orchid Epidendrum difforme in Nicaragua oil droplets, surrounded by circular chlorotic haloes and (Linder 1944). In Brazil, this rust has been reported on amphigenous (Figs 1, 2). Catasetum sp., Catasetum fimbriatum, Catasetum maranhense, Morphological features of the fungus were: uredinia on lower Cyrtopodium sp., Cyrtopodium punctatum, Epidendrum sp., leaf surfaces, subepidermal, erumpent, 200–550 Â 120–300 mm; Notylia lyrata, Plelurothallis mentigera, Prescottia sclerophylla, urediniospores ovoid, 25–35 Â 16–25 mm, cell wall 2.0–4.5 mm Sauroglossum nitidum, Spiranthes sp., Stanhopea graveolens, thick, germ pore indistinct, hyaline becoming pale yellowish Stenorrhynchus sp. and Zygostates lunata (Pereira et al.2002; with abundant coloured oil dropets (Fig. 3). Spermogonia, aecia Pereira and Barreto 2004; Hennen et al.2005;Silvaand and telia not observed. Material examined: VIC 30693, on leaves Figueiredo 2006). of Epidendrum secundum, Cachoeira da Esmeralda, Carrancas, This is the first report of S. kevorkianii attacking E. secundum state of Minas Gerais, Brazil, O.L. Pereira, 10 Apr. 2008; and E. xanthinum in Brazil. VIC 30694, on leaves of Epidendrum xanthinum, Araponga, state of Minas Gerais, Brazil, O.L. Pereira, 15 Jun. 2008. Based on Acknowledgements these characteristics the fungus was identified as Sphenospora We are grateful to Fundacão¸ de Amparo à Pesquisa do Estado de Minas kevorkianii. Gerais-FAPEMIG for providing financial support (project 279/07) and O. L. Pereira acknowledges the Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq research fellowship of this ongoing program (a) to survey and describe the phytopathogenic and the endophytic mycodiversity associated with the family Orchidaceae in the state of Minas Gerais.

References Hennen JF, Figueiredo MB, Carvalho AA, Hennen PG (2005) Catalogue of the Species of Plant Rust Fungi (Uredinales) of Brazil. Rio de Janeiro, RJ: Jardim Botânico do Rio de Janeiro. Linder DH (1944) A new rust of orchids. Mycologia 36, 464–468. doi: 10.2307/3754953 Pereira OL, Barreto RW (2004) First report of Sphenospora kevorkianii (Raveneliaceae) on the orchid Catasetum fimbriatum in Brazil. Plant Pathology 53, 256. doi: 10.1111/j.0032-0862.2004.00969.x Pereira OL, Cavallazzi JRP, Rollemberg CL, Kasuya MCM (2002) Sphenospora kevorkianii, a rust fungus (Uredinales: Raveneliaceae) on the orchid Pleurothallis mentigera. Brazilian Journal of Microbiology (b) 33, 155–156. doi: 10.1590/S1517-83822002000200011 Silva GS, Figueiredo MB (2006) Catasetum maranhense, um novo hospedeiro de Sphenospora kevorkianii (Uredinales). Summa Phytopathologica 32, 197. doi: 10.1590/S0100-54052006000200020 Silva M, Pereira OL (2007) First report of Guignardia endophyllicola leaf blight on Cymbidium (Orchidaceae) in Brazil. Australasian Plant Disease Notes 2,31–32. doi: 10.1071/DN07015 Silva M, Pereira OL (2008) Black mildew disease of the neotropical orchid Epidendrum secundum caused by Lembosia epidendri sp. nov. from Minas Gerais, Brazil. Mycotaxon 104, 385–390. Silva M, Pereira OL, Braga IF, Lelis SM (2008) Leaf and pseudobulb diseases on Bifrenaria harrisoniae (Orchidaceae) caused by Phyllosticta capitalensis in Brazil. Australasian Plant Disease Notes 3,53–56.

Fig. 3. (a) Cross-section of a diseased leaf showing erumpent uredinia with urediniospores. (b) Ovoid thick walled urediniospores (VIC 30694). Manuscript received 21 May 2009, accepted 25 May 2009

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