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First Report of Erysiphe quercicola Causing Powdery Mildew on Cashew in Brazil
2017; American Phytopathological Society; Volume: 101; Issue: 7 Linguagem: Inglês
10.1094/pdis-11-16-1658-pdn
ISSN1943-7692
AutoresJ. E. Cardoso, F. M. P. Viana, Márcio Akio Ootani, M. V. V. Martins, F. S. A. Araújo,
Tópico(s)Plant Pathogens and Fungal Diseases
ResumoHomePlant DiseaseVol. 101, No. 7First Report of Erysiphe quercicola Causing Powdery Mildew on Cashew in Brazil PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Erysiphe quercicola Causing Powdery Mildew on Cashew in BrazilJ. E. Cardoso, F. M. P. Viana, M. A. Ootani, M. V. V. Martins, and F. S. A. AraújoJ. E. CardosoSearch for more papers by this author, F. M. P. VianaSearch for more papers by this author, M. A. OotaniSearch for more papers by this author, M. V. V. MartinsSearch for more papers by this author, and F. S. A. AraújoSearch for more papers by this authorAffiliationsAuthors and Affiliations J. E. Cardoso F. M. P. Viana M. A. Ootani M. V. V. Martins F. S. A. Araújo , Embrapa Agroindústria Tropical, CEP 6060511-110, Fortaleza, CE Brazil. Published Online:11 Apr 2017https://doi.org/10.1094/PDIS-11-16-1658-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Cashewnut (Anacardium occidentale L.) is a very important crop plant native to northern Brazil. In 2010 and following years, a powdery mildew outbreak was observed in over 60% of cashew growing areas in coastal and highland fields in Ceará and Piauí states, which account for over 70% of Brazilian cashewnut production. Disease symptoms commonly appeared as white to gray powder on young shoots, inflorescences, young fruits, and leaves, reducing fruit onset and severely damaging apple and kernels. Highest level of infection was observed by the time of flowering and fruiting plant stages, which occurs from June to September in those particular states. Today, powdery mildew is the main pathological constraint of cashew production in Brazil, as it affects mature trees, nursery stocks, and new plantings. Although there is great variability within cashew genotypes, most growing varieties are susceptible. From 2012 until 2014, field surveys were conducted to collect samples from different environments and host genotypes. Severely infected flushing leaves of BRS 189 cashew clone were collected in Pacajus county, Ceará State, and introduced into the Laboratory of Plant Pathology, Embrapa, for further studies. Due to conspicuous differences between these and commonly known symptoms from early described powdery mildew (Noack 1898), morphological and sequence data molecular studies were then conducted in order to determine the causal fungus. Conidiophores were erect with cylindrical foot cells, average size 100.2 µm. Chasmothecia were absent. Primary conidia were ellipsoid, with a rounded apex and truncate base. Mature conidia were mainly dolioform and formed singly (no catenescent), measuring 26.9 to 31.7 µm long × 14.3 to 20.4 µm wide (avg. 29.9 × 14.8 µm), with length/width ratio of 1.8 on average. The internal transcribed spacer (ITS) region, including 5.8S and partial 28S from genomic DNA extracted, was amplified with ITS1F (5′-TCCGTAGGTGAACCTGCGG-3′) and P3 (5′-GCCGCTTCACTCGCCGTTAC-3′) primers. The amplicon was sequenced by external service (Macrogen, Seoul, South Korea). BLASTn analysis of the ITS sequence (661 pb) showed a high homology (identity: 100%, e-values: 0.0, coverage: 100%) with Erysiphe quercicola (GenBank accession no. KY172852). Five young 75-day-old grafted plants of cv BRS 189 were artificially inoculated and five noninoculated plants served as control, all grown under glasshouse conditions at 26 ± 2°C. Inoculations were made by brushing conidia from naturally disease leaves onto flushing young leaves. All inoculated plants developed powdery mildew symptoms after 10 days, whereas the control plants remained symptomless. Therefore, on the basis of morphological features and sequence data analysis, the causal fungus causing powdery mildew on young organs of cashew plants was determined to be E. quercicola. This fungus has been reported to cause powdery mildew on several tropical plant species including cashew reported in Tanzania (Voucher MUMH781, Mie University, Mycological Herbarium, Japan) (Limkaisang et al. 2006) under the anamorphic name of Pseudoidium anacardii, which is presently assigned as E. quercicola (Braun and Cook 2012). This is the first report of powdery mildew on young organs of cashewnut plants caused by E. quercicola in Brazil.References:Braun, U., and Cook, R. T. A. 2012. Taxonomic Manual of the Erysiphales (Powdery Mildews). CBS Biodiversity series No. 11. CBS, Utrecht, The Netherlands. Google ScholarLimkaisang, S., et al. 2006. Mycoscience 47:327. https://doi.org/10.1007/S10267-006-0311-Y Crossref, Google ScholarNoack, F. 1898. Boletim do Instituto Agronômico do Estado de São Paulo 9:75-88. Google ScholarDetailsFiguresLiterature CitedRelated Vol. 101, No. 7 July 2017SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 20 Jun 2017Published: 11 Apr 2017First Look: 27 Feb 2017Accepted: 22 Feb 2017 Page: 1327 Information© 2017 The American Phytopathological SocietyCited byAlternative hosts of Erysiphe quercicola in the Brazilian cashew ecosystem17 November 2022 | Plant Pathology, Vol. 15Disease-Causing Agents in Cashew: A Review in a Tropical Cash Crop18 October 2022 | Agronomy, Vol. 12, No. 10Erysiphe quercicolaCABI Compendium, Vol. CABI CompendiumErysiphe quercicola causing powdery mildew on Cassia fistula and Tamarindus indica in Brazil27 February 2021 | Australasian Plant Disease Notes, Vol. 16, No. 1Hosts of asexual morph of Erysiphe quercicola from Thailand3 February 2020 | Tropical Plant Pathology, Vol. 45, No. 2Clitoria fairchildiana, new host of anamorphic Erysiphe quercicola in Brazil29 June 2019 | Journal of General Plant Pathology, Vol. 85, No. 6Morphological, molecular phylogenetic and pathogenic analyses of Erysiphe spp. causing powdery mildew on cashew plants in Brazil3 June 2019 | Plant Pathology, Vol. 68, No. 6Enxofre versus acibenzolar-s-methyl no controle do oídio do cajueiro1 December 2018 | Summa Phytopathologica, Vol. 44, No. 4Reaction of commercial clones of cashew to powdery mildew in northeastern BrazilCrop Protection, Vol. 112Influência das épocas de floração e dos períodos de proteção fenológica à infecção do oídio no clone de cajueiro-anão BRS 1891 December 2017 | Revista Ceres, Vol. 64, No. 6
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