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First Report of Kalanchoe Leaf and Stem Spot Caused by Corynespora cassiicola in Denmark

2016; American Phytopathological Society; Volume: 101; Issue: 3 Linguagem: Inglês

10.1094/pdis-08-16-1173-pdn

1943-7692

Kenneth Madriz‐Ordeñana, Hans Jørgen Lyngs Jørgensen, Kai L. Nielsen, Hans Thordal‐Christensen,

Powdery Mildew Fungal Diseases

HomePlant DiseaseVol. 101, No. 3First Report of Kalanchoe Leaf and Stem Spot Caused by Corynespora cassiicola in Denmark PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Kalanchoe Leaf and Stem Spot Caused by Corynespora cassiicola in DenmarkK. Madriz-Ordeñana, H. J. L. Jørgensen, K. L. Nielsen, and H. Thordal-ChristensenK. Madriz-Ordeñanahttp://orcid.org/0000-0003-3133-0371Search for more papers by this author, H. J. L. JørgensenSearch for more papers by this author, K. L. NielsenSearch for more papers by this author, and H. Thordal-ChristensenSearch for more papers by this authorAffiliationsAuthors and Affiliations K. Madriz-Ordeñana H. J. L. Jørgensen , Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK-1871 Frederiksberg C, Denmark K. L. Nielsen , Knud Jepsen a/s, Skanderborgvej 193, 8382 Hinnerup, Denmark H. Thordal-Christensen , Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK-1871 Frederiksberg C, Denmark. Published Online:15 Dec 2016https://doi.org/10.1094/PDIS-08-16-1173-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Kalanchoe (Kalanchoe blossfeldiana Poelln.) is a succulent plant of great importance to the flower industry in Denmark. Denmark accounts for nearly one fourth of the European production of ∼200 million plants per year. In October 2015, we observed stems and leaves of Kalanchoe affected by what appeared to be a fungal disease in a commercial nursery in Denmark. It is estimated that up to 5 to 6% of the plants were affected at different growth stages. The symptoms were dark brown, sunken, necrotic lesions at the base of the plants, expanding to the stem and lower leaves. Severely affected plants showed extensive crown rotting and defoliation. The causal fungal pathogen was isolated from lesions on potato dextrose agar (PDA). Cultures were whitish-gray to light brown and darker underneath. Older cultures became uniformly dark brown. Microscope observation revealed cylindrical conidiophores, straight or slightly curved, and pale to light brown. Conidia had 2 to 19 septa and appeared light brown, straight or curved, cylindrical, and occasionally obclavate with a length of 15.9 to 239.1 µm (avg. 53.9 µm, n = 171) and a width of 4.9 to 10.9 µm (avg. 7.5 µm, n = 100). Based on this morphology, the fungus was identified as Corynespora cassiicola (Berk. & Curt.) Wei (Ellis and Holliday 1971). An isolate, CP2285, was deposited in our culture collection. The ribosomal ITS region of this isolate was sequenced (GenBank accession no. KX458107) and found to have over 99% nucleotide identity to ribosomal ITS sequences of several reported strains of C. cassiicola from different hosts, thus confirming its identity. Pathogenicity tests were carried out using cultivar Tender White. For this, four cuttings, with leaf and petiole, were placed in separate petri dishes containing filter paper soaked in sterile water. Inoculum (8 × 104 conidia·ml–1, 0.05% Tween 20) was obtained from 3-week-old PDA cultures. Three 80-µl drops of the inoculum were placed separately on each leaf and the petiole. Another four cuttings were mock-treated with water with 0.05% Tween 20. Initial lesions appeared in all inoculum-treated tissues after 3 days of incubation at room temperature (18 to 22°C), while extensive lesions occurred after 10 days, producing a symptom pattern identical to originally diseased plants. No symptoms appeared in the controls. To test whether C. cassiicola can infect Kalanchoe by spreading through the soil, we treated 14 newly planted, symptom-free cuttings by drenching the soil (pathogen-free commercial sphagnum) with 1 ml inoculum (8 × 104 conidia·ml–1, 0.05% Tween 20). Another 14 cuttings were mock-treated with water with 0.05% Tween 20. After 4 weeks of cultivation in the greenhouse, 9 out of the 14 inoculated plants showed characteristic leaf and stem spot lesions. None of the control plants were symptomatic. Microscopy of samples prepared from these experiments showed the presence of fungal structures characteristic of C. cassiicola, thus fulfilling Koch’s postulates. To our knowledge, this is the first report of leaf and stem spot caused by C. cassiicola in Kalanchoe in Denmark. Given the commercial importance of Kalanchoe, and the severity and wide distribution of C. cassiicola (Dixon et al. 2009), we consider this disease of particular significance for the successful production of Kalanchoe in Europe.References:Dixon, L. J., et al. 2009. Phytopathology 99:1015. https://doi.org/10.1094/PHYTO-99-9-1015 Link, ISI, Google ScholarEllis, M. B., and Holliday, P. 1971. Corynespora cassiicola. CMI Descriptions of Pathogenic Fungi and Bacteria, No. 303. Commonwealth Mycological Institute, Kew, Surrey, U.K. Google ScholarDetailsFiguresLiterature CitedRelated Vol. 101, No. 3 March 2017SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 9 Feb 2017Published: 15 Dec 2016First Look: 1 Nov 2016Accepted: 27 Oct 2016 Pages: 505-505 Information© 2017 The American Phytopathological SocietyCited byComplete genome sequence of a novel fusarivirus from the phytopathogenic fungus Corynespora cassiicola9 April 2022 | Archives of Virology, Vol. 167, No. 5Corynespora cassiicola (target leaf spot of tomato)CABI Compendium, Vol. CABI CompendiumA Biocascade Approach Towards the Recovery of High-Value Natural Products from Biowaste: State-of-Art and Future Trends7 May 2020 | Waste and Biomass Valorization, Vol. 12, No. 3Prevalence of Soil-borne Diseases in Kalanchoe blossfeldiana Reveals a Complex of Pathogenic and Opportunistic FungiKenneth Madriz-Ordeñana, Hans Jørgen Lyngs Jørgensen, Andreea Balan, Daniel Madriz Sørensen, Kai Lønne Nielsen, and Hans Thordal-Christensen24 July 2019 | Plant Disease, Vol. 103, No. 10Soil Microbial Assemblages Are Linked to Plant Community Composition and Contribute to Ecosystem Services on Urban Green Roofs11 June 2019 | Frontiers in Ecology and Evolution, Vol. 7Kalanchoë26 July 2018