Harun BAYRAKTAR, Rıza KAYA, Gülsüm PALACIOĞLU, Meltem AVAN, Yakup Zekai KATIRCIOĞLU, Tülin SARIGÜL ERTEK, Salih MADEN

Sugar beet root rot caused by oomycetous pathogens in Turkey and their control by seed treatment

The aim of this study was to determine the oomycetous pathogens causing root rot on sugar beet and test their control by seed treatment in Konya Province, Turkey. Oomycetous fungus-like pathogens of sugar beet were investigated using 866 plant samples collected at 2 growth stages, early seedling and late root, from fields in the Konya region of Turkey and 1 sample from the Thrace region. Herein, 10 oomycetous species belonging to 3 genera: Aphanomyces cochlioides, Phytophthora cryptogea, Ph. pseudocryptogea, Ph. megasperma, Ph. inundata, Pythium aphanidermatum, Py. helicoides, Py. heterothallicum, Py. sylvaticum, and Py. ultimum var. ultimum (Globisporangium ultimum var. ultimum) were discovered at various times with in the 2 growth periods, all of which were the first records for Turkey. A. cochlioides was the most serious pathogen, both in terms of its wide distribution and aggressiveness. The pathogen produced more than 90% disease severity when tested by soil infestation at the seedling stage, although it also occurred at the late root growth stage. Pythium species were also ascommon, such as A. cochlioides, the majority of which were very aggressive, producing more than 84% disease severity at the seedling stage, except for Py. aphanidermatum. Half-strength potato dextrose agar medium was found to be very useful for the isolation of all of the pathogens from the plant samples at both stages. Morphological features of all of the pathogens were abundantly produced when the pathogens were grown on amended grated carrot agar medium and culture disks of fungal growth of this medium were submerged in sterile and nonsterile soil extracts. Out of the 15 fungicide mixes tested, 2 mixes, thiram+metalaxyl+hymexazole and thiram+metalaxyl+hymexazole+ pyraclostrobin reduced seedling root rot caused by both A. cochlioides and Pythium ultimum var. ultimum, while the standard seed treatment fungicide mix of thiram+hymexazole was not effective against either of the pathogens.

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Akıllı S, Ulubaş-Serçe Ç, KatırcıoğluYZ, Maden S (2012). Involvement of Phytophthora spp. in chestnut decline in the Black Sea region of Turkey. Forest Pathology 42 (5): 377-386.
Avan M, Aksoy C, Katırcıoğlu YZ, Demirci F, Kaya R (2019). First report of Aphanomyces cochlioides causing root rot of sugar beet in Turkey. New Disease Reports 39: 22.
Babai-Ahary A, Abrinnia M, Heravan IM (2004). Identification and pathogenicity of Pythium species causing damping-off in sugarbeet in northwest Iran. Australasian Plant Pathology 33 (3): 343-347.
Brantner JR, Windels CE (1998). Variability in sensitivity to metalaxyl in vitro, pathogenicity, and control of Pythium spp. on sugar beet. Plant Disease 82: 896-899.
Coffey MD, Bower LA (1984). In vitro variability among isolates of six Phytophthora species in response to metalaxyl. Phytopathology 74: 502-506.
Cook RJ, Zhang BX (1985). Degrees of sensitivity to metalaxyl within the Pythium spp. pathogenic to wheat in the Pacific Northwest. Plant Disease 69: 686-688.
Csinos AS, Bertrand PF(1994). Distribution of Phytophthora parasitica var. nicotianae races and their sensitivity to metalaxyl in Georgia. Plant Disease 78: 471-474.
Erwin DC, Ribeiro OK (2005). Phytophthora diseases worldwide. St. Paul, MN, USA: The American Phytopathological Society
Erzurum K, Seçer E, Ertunç F, Maden S (1995). Çorum, Kastamonu ve Turhal şeker fabrikaları ekim bölgelerinde şeker pancarında fungal kök çürüklük etmenlerinin tespiti. In: VII. Türkiye Fitopatoloji Kongresi; Adana, Turkey. pp. 122-125 (in Turkish).
Gallegly ME, Hong C (2008). Phytophthora: Identifying species by morphology and DNA fingerprints. St. Paul, MN, USA: The American Phytopathological Society.
Goodwin SB, McGrath MT (1995). Insensitivity to metalaxyl among isolates of Phytophthora erythroseptica causing pink rot of potato in New York. Plant Disease 79: 967.
Harveson RM, Hanson LE, Hein GL (2009). Compendium of beet diseases and pests. St. Paul, MN, USA: The American Phytopathological Society (APS Press).
Jacobsen B (2006). Root rot diseases of sugar beet. Zbornik Matica Srpske za prirodne nauke 110: 9-19.
Jeffers SN (2006). Identifying species of Phytophthora. SC, Clemson University, Clemson, SC, USA.
Kuznia R, Windels CE (1993). Identification and pathogenicity of Pythium spp. isolated from sugarbeet-1992 sugarbeet research extension report. Crookston, MN, USA: University of Minnesota (Northwest Experiment Station).
Leach LD (1986). Seedling diseases. In: Whitney ED, Duffus JE (editors). Compendium of beet diseases and insects. St. Paul, MN, USA: The American Phytopathological Society,, pp. 4-8.
Mathews PG (2005). Design of experiments with MINITAB. Milwaukee, WI, USA: American Society for Quality, Quality Press.
Özgönen H, Çulal Kılıç H (2009). Isparta ili şeker pancarı ekim alanlarında fungal hastalıkların ve yaygınlık oranlarının belirlenmesi. Süleyman Demirel Üniversitesi Ziraat Fakültesi Dergisi 4 (1): 16-22 (in Turkish).
Pfender WF, Delwiche PA, Grau CR, Hagedorn DJ (1984). A medium to enhance recovery of Aphanomyces from infected plant tissue. Plant Disease 68: 845-847.
Pizczek J (2004). Occurrence of root rot of sugar beet cultivars. Journal of Plant Protection Research 44 (4): 341-345.
Rush CM (1987). Root rot of sugar beet caused by Pythium deliense In the Texas Panhandle. Plant Disease 71 (5): 468-469.
Safaiefarahani B, Mostowfizadeh-Ghalamfarsa R, Hardy GSJ, Burgess TI (2015). Re-evaluation of the Phytophthora cryptogea species complex and the description of a new species, Phytophthora pseudocryptogea sp. nov. Mycological Progress 14 (11): 108.
Scott PT, Martin HL, Boreel SM, Wearing AH, Maclean DJ (2005). Molecular characterisation, pathogenesis and fungicide sensitivity of Pythium spp. from table beet (Beta vulgaris var. vulgaris) grown in the Lockyer Valley, Queensland. Australasian Plant Pathology 34 (3): 361-368.
Stamps DJ, Waterhouse GM, Newhook FJ, Hall GS (1990). Revised tabular key to the species of Phytophthora. Mycological Papers 162: 28.
Tamura K, Stecher G, Peterson D, Filipski A, Kumar S (2013). MEGA6: molecular evolutionary genetics analysis version 6.0. Molecular Biology and Evolution 30 (12): 2725-2729.
Van der Plaats-Niterink AJ (1981). Monograph of the genus Pythium. Studies in Mycology 21: 1-44.
White JG, Stanghellini ME, Ayoubi LM (1988). Variation in the sensitivity to metalaxyl of Pythium spp. isolated from carrot and other sources. Annals of Applied Biology 113: 269-277.
White TJ, Bruns T, Lee S, Taylor J (1990). Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. PCR Protocols: A Guide to Methods and Applications 18 (1): 315-322.
Wilcox JS, Ellis MA (1989). Phytophthora root and crown rots of peach trees in eastern great lakes region. Plant Disease 73: 794- 798.
Windels CE (2000). Aphanomyces root rot on sugar beet. Plant Health Progress 1 (1): 8.
Yorgancı Ü, Turhan G (1988). Untersuchungen über den Weichfaeule erzeugenden Erregerkomplex an Zückerrüben. The Journal of Turkish Phytopathology 17 (2): 57-66