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Description and identification of two new diseases of guariroba palm (Syagrus oleraceae) in Brazil

Author:
Cardoso, Jéssica K. B., Nanami, Danielle S. Y., Zanutto, Carlos A., Grabicoski, Edilaine M. G., Vida, João B., Bock, Clive H., Nunes, William M. C.
Source:
Phytopathologische Zeitschrift 2017 v.165 no.9 pp. 610-619
ISSN:
0931-1785
Subject:
Alternaria tenuissima, Pestalotiopsis, Syagrus, color, etiology, fungi, fungicides, indigenous species, internal transcribed spacers, leaf spot, ribosomal DNA, seedlings, Brazil
Abstract:
Guariroba is a palm species native to central Brazil. Seedlings of guariroba with leaf spots of unknown aetiology were found in Patos de Minas, Minas Gerais, Brazil. The leaf spots were manifest as two different symptom types: the first lesion type consisted of necrotic spots with a rounded to elongate shape, with a light colour and dark edges; the second lesion type had a rounded shape, was dark brown in colour with a light brown edge. The objective of this study was to elucidate the aetiology of both diseases. The likely causal agents were isolated and Koch's postulate fulfilled. Subsequently, the ITS region of rDNA from both micro‐organisms were amplified and sequenced. According to the morphological characteristics and molecular analyses, the fungal species were identified as Pestalotiopsis adusta (causing necrotic spots with a rounded to elongate shape, with a light colour and dark edges), and Alternaria tenuissima (causing lesions with a rounded shape, dark brown in colour with a light brown edge). Identification of the causal organisms of these two diseases will help guide management approaches that might be tested to reduce impact of the disease on Guariroba, including the use of fungicides and cultural approaches.
Agid:
5776206