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First Report of Cordon Dieback of Kiwifruits Caused by Diaporthe ambigua and D. australafricana in Chile

2017; American Phytopathological Society; Volume: 102; Issue: 2 Linguagem: Inglês

10.1094/pdis-07-17-1105-pdn

1943-7692

Gonzalo A. Díaz, B. A. Latorre,

Mycorrhizal Fungi and Plant Interactions

HomePlant DiseaseVol. 102, No. 2First Report of Cordon Dieback of Kiwifruits Caused by Diaporthe ambigua and D. australafricana in Chile PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Cordon Dieback of Kiwifruits Caused by Diaporthe ambigua and D. australafricana in ChileG. A. Díaz and B. A. LatorreG. A. DíazSearch for more papers by this author and B. A. Latorre†Corresponding author: B. A. Latorre; E-mail: E-mail Address: blatorre@uc.clSearch for more papers by this authorAffiliationsAuthors and Affiliations G. A. Díaz , Laboratorio de Patología Frutal, Departamento de Producción Agrícola, Facultad de Ciencias Agrarias, Universidad de Talca, Campus Lircay, Talca, Chile B. A. Latorre † , Departamento de Fruticultura y Enología, Pontificia Universidad Católica de Chile. Published Online:4 Dec 2017https://doi.org/10.1094/PDIS-07-17-1105-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat A cordon dieback of kiwifruit (Actinidia deliciosa) cultivar Hayward was observed in 16 orchards in Chile (Quillota to Linares) in 2013 to 2015. Prevalence varied greatly from 5 to 75%. Symptomatic plants of >9 years showed short internodes, weak shoots, small and chlorotic leaves, and cane and cordon dieback. Brown, irregular, hard cankers were observed in cross sections of diseased cordons. Cordon samples (n = 80) were surface disinfected (96% ethanol for 10 s and flamed for 8 s), and pieces (2 to 3 cm in length) from the edges of cankered tissues were plated on potato dextrose agar (PDA) plus 0.1% Igepal detergent (octylphenoxy poly[ethyleneoxy]ethanol, branched) (Sigma-Aldrich) for 7 days at 20°C (Díaz and Latorre 2014). Isolates (n = 47) developing white to creamy fast-growing colonies with black-globose pycnidia were obtained after 30 days. All isolates produced hyaline, one-cell, biguttulate, and ellipsoidal α conidia of 5.3 to 7.6 × 2.4 to 3.1 µm and were identified as Diaporthe (Phomopsis) spp. (Gomes et al. 2013). To determine the species identity, six isolates were sequenced using PCR amplification of the rDNA internal transcribed spacer (ITS4/ITS5) and translation elongation factor 1-α gene (EF728/EF968) (Gomes et al. 2013). ITS and EF1-α sequences of three isolates (GenBank accession nos. KU679325 to KU679327 and KU695196 to KU695198, respectively) were 100% identical to the ex-epitype (CBS 114015) of Diaporthe ambigua Nitschke (GenBank accession nos. KC343010 and KC343736 for ITS and EF1-α, respectively). ITS and EF1-α sequences of the other three isolates (GenBank accession nos. KU679315 to KU679317 and KU695186 to KU695188, respectively) were 100% identical to the ex-type (CBS 111886) of Diaporthe australafricana Crous & Van Niekerk (GenBank accession nos. KC343038 and KC343764 for ITS and EF1-α, respectively). Pathogenicity tests were conducted with D. ambigua, isolate Dam KM-5, and D. australafricana, isolate Daus KM-13, on canes (n = 16) and 3-year-old trunks (n = 10) of Hayward kiwifruit in winter months. Canes were pruned and immediately inoculated with 20 µl of conidial suspension (106 α-conidia/ml). Trunk inoculations were performed at the trunk base with a 5 mm mycelial plug, taken from 7-day-old colonies on PDA, and placed aseptically in wounds made with a corker borer. An equal number of canes inoculated with sterile water and trunks inoculated with sterile agar plugs served as controls. On canes, necrotic lesions of 66 and 94 mm in length were caused by D. ambigua and D. australafricana, respectively, 9 months after inoculation. Trunk necrotic lesions of 51 and 62 mm were obtained with D. ambigua and D. australafricana, respectively, 12 months after inoculation. Reisolations were successful from inoculated tissues, and isolates were reidentified molecularly, completing Koch’s postulates. Noninoculated controls remained symptomless. To our knowledge, this is the first report of cordon dieback caused by D. ambigua and D. australafricana in kiwifruit worldwide. Previously, D. ambigua and D. australafricana have been reported causing blueberry stem canker and kiwifruit rots in Chile (Díaz et al. 2017; Elfar et al. 2013). Previously, D. actinidiae was associated to kiwifruit dieback in Chile (Palma and Piontelli 2000). The understanding of the pathogens associated to kiwifruit cane dieback can help to improve management practices to prevent severe damages.References:Díaz, G. A., et al. 2017. Plant Dis. 101:1402. https://doi.org/10.1094/PDIS-10-16-1535-RE Link, ISI, Google ScholarDíaz, G. A., and Latorre, B. A. 2014. Plant Dis. 98:351. https://doi.org/10.1094/PDIS-12-12-1180-RE Link, ISI, Google ScholarElfar, K., et al. 2013. Plant Dis. 97:1042. https://doi.org/10.1094/PDIS-11-12-1030-RE Link, ISI, Google ScholarGomes, R. R., et al. 2013. Persoonia 31:1. https://doi.org/10.3767/003158513X666844 Crossref, ISI, Google ScholarPalma, A., and Piontelli, E. 2000. Bol. Micolog. 15:79. Google ScholarFondecyt, Project no. 3140304.DetailsFiguresLiterature CitedRelated Vol. 102, No. 2 February 2018SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 19 Jan 2018Published: 4 Dec 2017First Look: 9 Oct 2017Accepted: 29 Sep 2017 Page: 446 Information© 2018 The American Phytopathological SocietyCited byFirst Report of Diaporthe ambigua Associated with Dead Arm Disease on Grapevine in ChileA. Larach, N. Riquelme, A. Salinas, P. E. Rolshausen, M. Seeger, and X. Besoian27 May 2022 | Plant Disease, Vol. 106, No. 7Diaporthe ambigua (canker: pear)CABI Compendium, Vol. CABI CompendiumDiaporthe australafricanaCABI Compendium, Vol. CABI CompendiumIdentification and Pathogenicity of Diplodia, Neofusicoccum, Cadophora, and Diaporthe Species Associated with Cordon Dieback in Kiwifruit cultivar Hayward in Central ChileGonzalo A. Díaz, Juan Pablo Zoffoli, Enrique E. Ferrada, and Mauricio Lolas6 April 2021 | Plant Disease, Vol. 105, No. 5First Report of Peroneutypa scoparia Causing Cane Dieback in Kiwifruit in ChileA. Castilla-Cayuman, M. Lolas, and G. A. Díaz13 December 2018 | Plant Disease, Vol. 103, No. 2