First Report of Podosphaera macularis Causing Hop (Humulus lupulus) Powdery Mildew in Brazil

HomePlant DiseaseVol. 105, No. 8First Report of Podosphaera macularis Causing Hop (Humulus lupulus) Powdery Mildew in Brazil PreviousNext DISEASE NOTE OPENOpen Access licenseFirst Report of Podosphaera macularis Causing Hop (Humulus lupulus) Powdery Mildew in BrazilMariana Mendes Fagherazzi, Fernando Sartori Pereira, Francine Regianini Nerbass, Evandro Ferreira Zacca, Vinícius Bizolo Sommer, Mayra Juline Gonçalves, Leo Rufato, Ricardo Trezzi Casa, Amauri Bogo, and Fabio Nascimento da SilvaMariana Mendes Fagherazzihttps://orcid.org/0000-0001-6318-6816Crop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, BrazilSearch for more papers by this author, Fernando Sartori PereiraCrop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, BrazilSearch for more papers by this author, Francine Regianini NerbassCrop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, BrazilSearch for more papers by this author, Evandro Ferreira ZaccaCrop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, BrazilSearch for more papers by this author, Vinícius Bizolo SommerCrop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, BrazilSearch for more papers by this author, Mayra Juline Gonçalves†Corresponding author: M. J. Gonçalves; E-mail Address: mayra.juline@hotmail.comhttps://orcid.org/0000-0001-9098-5306Crop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, BrazilSearch for more papers by this author, Leo RufatoCrop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, BrazilSearch for more papers by this author, Ricardo Trezzi CasaCrop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, BrazilSearch for more papers by this author, Amauri BogoCrop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, BrazilSearch for more papers by this author, and Fabio Nascimento da SilvaCrop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, BrazilSearch for more papers by this author AffiliationsAuthors and Affiliations Mariana Mendes Fagherazzi Fernando Sartori Pereira Francine Regianini Nerbass Evandro Ferreira Zacca Vinícius Bizolo Sommer Mayra Juline Gonçalves † Leo Rufato Ricardo Trezzi Casa Amauri Bogo Fabio Nascimento da Silva Crop Production Graduate Program, Santa Catarina State University/UDESC, 88.520-000, Lages, Santa Catarina, Brazil Published Online:15 Sep 2021https://doi.org/10.1094/PDIS-01-21-0094-PDNAboutSectionsView articlePDFPDF PlusSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleThe hop (Humulus lupulus L.) is a dioecious perennial climbing plant grown commercially worldwide. Wild hops are widely distributed throughout the Northern Hemisphere, Europe, Asia, and North America (Neve 1991). In the Southern Hemisphere, some of the leading hop-producing countries include South Africa, Australia, and New Zealand. Brazil began hop production less than 5 years ago. In January 2019, amphigenous white powdery circular fungal colonies were observed on the leaves and stems of hop plants (cultivar ‘Chinook’) within a 900-m2 hop garden in Lages municipality, Santa Catarina State, southern Brazil. The disease was present on almost 100% of Chinook cultivar plants, and diseased foliage was collected to identify the pathogen and used to inoculate healthy plants. Hop powdery mildew lesions with hyaline and septate mycelium with chains of unicellular conidia (n = 100), hyaline, barrel-shaped, mean of length/width ± standard deviation 25 to 27 × 13 to 18 µm ± 0.980, with fibrosin bodies, and conidiophores erect with cylindrical foot cells, were visible within 10 days. The causal agent was identified as Podosphaera macularis (Wallr.:Fr.) Lind (synonym S. humuli [DC.] Burrill) on the basis of conidial shape, size, and host range (Braun 1987; Mahaffee et al. 2009; Royle 1978), complemented with the present molecular analysis. Chasmothecia have not been observed in the field to date. A conidial suspension of 200 ml at concentration of 1.4 × 105 was mixed with 5 µl of Tween 20 for the pathogenicity assay. Ten plants of 9-month-old hop (cv. Chinook) were inoculated with 5 ml of the conidial suspension using a manual spray. The control plot was only sprayed with water. The inoculated plants were maintained at 22 ± 1°C with a 12-h photoperiod and 65% relative humidity. White mycelia were visible first on the adaxial leaf surfaces of the inoculated younger leaves after 10 days, and the disease severity reached between 2 and 5%. No symptoms were observed at the control plot. P. macularis infected most aerial plant tissues of the inoculated plants and caused losses of approximately 50% of cones. P. macularis conidia were collected from the infected leaf tissue with a sterile soft camel-hair brush, and DNA was extracted using a Wizard Genomic DNA extraction kit. The primers ITS1/ITS4 (White et al. 1990) were used to amplify and sequence a fragment of the ITS region. PCR products were subjected to Sanger sequencing to confirm sample species. The resulting 522-bp sequence was deposited into GenBank (accession no. MN630490). BLASTn showed a 99.81% sequence identity with the CT1 isolate of P. macularis from H. lupulus (MH687414). The presence and identification of P. macularis in hop production regions is a new challenge to growers in Brazil. Research related to the knowledge of the disease cycle, epidemiology, and control strategies for the integrated management should be conducted, as there are no registered fungicides for powdery mildew on hop in Brazil. To our knowledge, this is the first report of P. macularis in Brazil, as well as in South America.The author(s) declare no conflict of interest.References:Braun, U. 1987. Page 113 in: A Monograph of the Erysiphales (Powdery Mildews). J. Cramer, Berlin, German Democratic Republic. Google ScholarMahaffee, W. F., et al. 2009. Compendium of Hop Diseases and Pests. American Phytopathological Society, Saint Paul, MN. Google ScholarNeve, R. A. 1991. Hops. Chapman and Hall, London, U.K. https://doi.org/10.1007/978-94-011-3106-3 Crossref, Google ScholarRoyle, D. J. 1978. Page 381 in: The Powdery Mildews. Academic Press, New York, NY. Google ScholarWhite, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. Google ScholarThe author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Vol. 105, No. 8 August 2021SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionComparison of banana plants in silicon-deficient soil amended or nonamended with calcium silicate and infected by Fusarium oxysporum f. sp. cubense (W. Zellner et al.). Photo credit: A. A. Fortunato and F. A. Rodrigues. Infected spicebush tree outer bark showing black vascular discoloration of the sapwood typical of laurel wilt (R. Olatinwo et al.). Photo credit: R. Olatinwo. Maize plants naturally infected by Bipolaris zeicola (S. S. Liu et al.). Photo credit: S. S. Liu. Metrics Downloaded 539 times Article History Issue Date: 1 Dec 2021Published: 15 Sep 2021First Look: 23 Mar 2021Accepted: 17 Mar 2021 Page: 2243 Information© 2021 The American Phytopathological SocietyKeywordsepidemiologydiagnosisdiseaseThe author(s) declare no conflict of interest.PDF download