First report of Didymosphaeria rubi-ulmifolii associated with canker and dieback of apple trees in southern Ethiopia

Cultivation of apple trees in the highlands of Ethiopia began in 1955. In 2014, blistering of the bark due to cankers on the main stems mostly below the grafting points, followed by dieback and eventually death of apple trees, was observed in apple orchards in the Hadiya Zone in Ethiopia. This study...

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Main Authors: Abraham YIRGU, Alemu GEZAHGNE, Tesfaye ALEMU, Minette HAVENGA, Lizel MOSTERT
Format: Article
Language:English
Published: Firenze University Press 2021-09-01
Series:Phytopathologia Mediterranea
Subjects:
Online Access:https://oajournals.fupress.net/index.php/pm/article/view/12400
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author Abraham YIRGU
Alemu GEZAHGNE
Tesfaye ALEMU
Minette HAVENGA
Lizel MOSTERT
author_facet Abraham YIRGU
Alemu GEZAHGNE
Tesfaye ALEMU
Minette HAVENGA
Lizel MOSTERT
author_sort Abraham YIRGU
collection DOAJ
description Cultivation of apple trees in the highlands of Ethiopia began in 1955. In 2014, blistering of the bark due to cankers on the main stems mostly below the grafting points, followed by dieback and eventually death of apple trees, was observed in apple orchards in the Hadiya Zone in Ethiopia. This study aimed to identify the causal agent of canker and dieback symptoms on the apple trees. Symptomatic trunks from 20 trees (ten per cultivar) were sampled. Isolations were performed from ten trunks (five per cultivar). Fungus colonies with similar cultural features were obtained from all the samples, and the morphology of a representative isolate was characterized. Phylogenetic analyses of the concatenated internal transcribed spacers 1 and 2 and 5.8S rRNA gene, large subunit and actin gene regions confirmed the identity of two isolates as Didymosphaeria rubi-ulmifolii. Pathogenicity was confirmed for one isolate by inoculations of healthy branches of ‘Anna’ and ‘Dorsett Golden’ apple trees resulting in lesion formation, and subsequent re-isolation of the inoculated fungus. This study is the first report of D. rubi-ulmifolii associated with dieback of apple trees. This pathogen caused death of more than 26% of apple trees in one commercial orchard, and could cause severe losses for smallholder apple growers in Ethiopia. Future studies are required to assess the magnitude, distribution and management options of this economically important canker disease in Ethiopia.
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spelling doaj.art-2e162fc7df5745579794eee0a4f1ded92022-12-21T19:31:29ZengFirenze University PressPhytopathologia Mediterranea0031-94651593-20952021-09-0160210.36253/phyto-12400First report of Didymosphaeria rubi-ulmifolii associated with canker and dieback of apple trees in southern EthiopiaAbraham YIRGU0Alemu GEZAHGNE1Tesfaye ALEMU2Minette HAVENGA3Lizel MOSTERT4Central Ethiopia Environment and Forest Research Center, P.O.Box 33042, Addis AbabaCentral Ethiopia Environment and Forest Research Center, P.O.Box 33042, Addis AbabaCollege of Natural and Computational Sciences, Addis Ababa University P.O.Box 1176Department of Plant Pathology, Stellenbosch University, Private Bag X1, Matieland, 7602Department of Plant Pathology, Stellenbosch University, Private Bag X1, Matieland, 7602Cultivation of apple trees in the highlands of Ethiopia began in 1955. In 2014, blistering of the bark due to cankers on the main stems mostly below the grafting points, followed by dieback and eventually death of apple trees, was observed in apple orchards in the Hadiya Zone in Ethiopia. This study aimed to identify the causal agent of canker and dieback symptoms on the apple trees. Symptomatic trunks from 20 trees (ten per cultivar) were sampled. Isolations were performed from ten trunks (five per cultivar). Fungus colonies with similar cultural features were obtained from all the samples, and the morphology of a representative isolate was characterized. Phylogenetic analyses of the concatenated internal transcribed spacers 1 and 2 and 5.8S rRNA gene, large subunit and actin gene regions confirmed the identity of two isolates as Didymosphaeria rubi-ulmifolii. Pathogenicity was confirmed for one isolate by inoculations of healthy branches of ‘Anna’ and ‘Dorsett Golden’ apple trees resulting in lesion formation, and subsequent re-isolation of the inoculated fungus. This study is the first report of D. rubi-ulmifolii associated with dieback of apple trees. This pathogen caused death of more than 26% of apple trees in one commercial orchard, and could cause severe losses for smallholder apple growers in Ethiopia. Future studies are required to assess the magnitude, distribution and management options of this economically important canker disease in Ethiopia.https://oajournals.fupress.net/index.php/pm/article/view/12400Malus pumilaParaconiothyrium brasiliensestem canker
spellingShingle Abraham YIRGU
Alemu GEZAHGNE
Tesfaye ALEMU
Minette HAVENGA
Lizel MOSTERT
First report of Didymosphaeria rubi-ulmifolii associated with canker and dieback of apple trees in southern Ethiopia
Phytopathologia Mediterranea
Malus pumila
Paraconiothyrium brasiliense
stem canker
title First report of Didymosphaeria rubi-ulmifolii associated with canker and dieback of apple trees in southern Ethiopia
title_full First report of Didymosphaeria rubi-ulmifolii associated with canker and dieback of apple trees in southern Ethiopia
title_fullStr First report of Didymosphaeria rubi-ulmifolii associated with canker and dieback of apple trees in southern Ethiopia
title_full_unstemmed First report of Didymosphaeria rubi-ulmifolii associated with canker and dieback of apple trees in southern Ethiopia
title_short First report of Didymosphaeria rubi-ulmifolii associated with canker and dieback of apple trees in southern Ethiopia
title_sort first report of didymosphaeria rubi ulmifolii associated with canker and dieback of apple trees in southern ethiopia
topic Malus pumila
Paraconiothyrium brasiliense
stem canker
url https://oajournals.fupress.net/index.php/pm/article/view/12400
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