Suppression and Molecular identification of severe Cercospora beticola causing Cercospora leaf spot disease on sugar beet

Sehsah, Mohamed D.; Omara, Reda Ibrahim; Elsayed, Samar S.A.; Abdelghany, Walaa R.; Saad El-Din, Heba I.; Afifi, Heba

doi:10.21608/jpfs.2023.259788.1006

Suppression and Molecular identification of severe Cercospora beticola causing Cercospora leaf spot disease on sugar beet

Document Type : Original Article

Authors

¹ Plant Pathology Research Institute, Agricultural Research Center, Giza 12619, Egypt

² Plant Pathology Research Institute, Agricultural Research Center, 12619, Giza, Egypt.

³ Gene Bank, Agriculture Research Center, Giza, Egypt.

10.21608/jpfs.2023.259788.1006

Abstract

Cercospora leaf spot disease, triggered by Cercospora beticola, poses a substantial threat to sugar beet varieties. Evaluation of nineteen sugar beet varieties indicated that Perfekta, Smart meyra KWS, Aseel, and Vulkhan exhibited the lowest disease severity and incidence. At the same time, Polylias, BTS 3880, Prilive, Faralda Kws, Zoom, and Smart Seza KWS showed higher susceptibility. The causal organism was isolated from diseased sugar beet plants in Kafrelshiekh, Behira, and Dakahlia governorates during the 2020 growing season. Twenty-seven fungal isolates were obtained and evaluated for aggressiveness on susceptible sugar beet variety (Polylias cv). Phylogenetic analysis using ITS sequences revealed genetic variations among the four most aggressive isolates, which were subsequently registered in NCBI. Furthermore, the efficacy of essential oils Citronella and Rose Geranium (Pelargonium graveolens) in controlling C. beticola was examined. Pelargonium graveolens at 10 ml/L demonstrated the highest effectiveness in reducing fungal growth, as well as in increasing total soluble solids content and sucrose. Additionally, this essential oil enhanced the activity of polyphenol oxidase and peroxidase enzymes. Scanning electron microscopy (SEM) examination confirmed that Citronella and Pelargonium graveolens, along with the fungicide montoro 30%, induced plasmolysis, decomposition, and damage to conidiophores and conidiospores of C. beticola, contrasted to the control treatment. This integrated approach, combining molecular characterization, disease evaluation, and essential oil application, provides valuable insights for the management of Cercospora leaf spot on sugar beet, offering sustainable and environmentally friendly alternatives to traditional fungicides.

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