Cercospora leaf spot (CLS; causal agent Cercospora beticola Sacc.) is endemic in many sugar beet production regions due to the widespread distribution of C. beticola and the inability of current management practices to provide complete control of the disease. Roots harvested from plants with CLS, therefore, are inevitably incorporated into sugar beet root storage piles, even though the effects of CLS on root storage properties are largely unknown. Research was conducted to determine the effects of CLS on storage properties including root respiration rate, sucrose loss, invert sugar accumulation, loss in recoverable sucrose yield, and changes in sucrose loss to molasses with respect to CLS disease severity and storage duration. Roots were obtained from plants with four levels of CLS severity in each of three production years, stored at 5°C and 95% relative humidity for up to 120 days, and evaluated for storage characteristics after 30, 90, and 120 days storage. No significant or repeatable effects of CLS on root respiration rate, sucrose loss, invert sugar accumulation, loss in recoverable sucrose yield, or change in sucrose loss to molasses were detected after 30, 90, or 120 days storage regardless of the severity of CLS disease symptoms. Therefore, no evidence was found that CLS accelerates sugar beet storage losses, and it is concluded that roots harvested from plants with CLS can be stored without additional or specialized precaution, regardless of CLS symptom severity.

Sugar beet (Beta vulgaris L.) is a globally important crop for sugar. In May 2019, sugar beet seedlings were observed with wilting, lodging and a few were dead in Glendive (46.970170, -104.838204), Montana. Symptoms appeared near the soil line as the stem (hypocotyl) turned dark brown to black with characteristic thread-like infections which resembled Pythium damping-off. It affected approximately 10% of the growing seedlings. Diseased sugar beet root tissues were excised with a sterile scalpel and small pieces (10 mm²) were surface sterilized with 70 % ethanol for 30 seconds, rinsed twice with autoclaved water, air-dried and transferred to potato dextrose agar (PDA) media amended with pimaricin-vancomycin-PCNB (Conway, 1985). Four plates were incubated at 25° C in the dark (Masago et al., 1977) and two weeks later white, dense colony was observed (Zhang et al., 2018). The terminal smooth, globose oogonia (average 18.5 µm in diameter) and antheridia (average 14.5 × 9.5 µm) extended below the oogonium were observed via VWR N. A. 0.30 microscope. The morphological features of the four isolates were consistent with Pythium ultimum Trow (Watanabe, 2002). Genomic DNAs (NORGEN BIOTEK CORP, Fungi DNA Isolation Kit #26200) of four isolates were used for polymerase chain reaction (PCR) with the ITS6-ITS7 primers (Taheri et al., 2017). Subsequently, PCR products were flushed by E.Z.N.A ®Cycle Pure Kit, OMEGA and four samples were sent for Sanger sequencing to GenScript (GenScript, Piscataway, NJ). The sequences were identical and submitted to GenBank, NCBI (accession no. MN398593). The NCBI Blast analysis showed 100% sequence homology to Pythium ultimum with the following GenBank accessions; KF181451.1, KF181449.1 and AY598657.2. Pathogenicity test was done on sugar beet with the same isolates in the greenhouse. Two week old, pythium culture was mixed with vermiculite and perlite mixer (PRO-MIX FLX) in the plastic trays (24´´ x 15´´× 3˝), (22 °C, 75% Relaive Humidity). Sterile water (500 ml/each tray) was added in the mixer to provide sufficient moisture. Twenty seeds of cv. Hilleshog 4302 were sown in the tray, and the trays were replicated thrice with inoculated and mock treatments. Plants were watered as needed to maintain adequate soil moisture conducive for plant growth and disease development. Seven days after sowing, 50% and 100% germination was observed in the inoculated and control treatments, respectively. At the beginning of the second week, 30% post-emergence damping-off was observed in the inoculated treatments. Diseased seedlings were gently pulled out from the pots where similar symptoms were observed in the sugar beet seedlings as described previously. No incidence of disease was observed in mock-treated seedlings. Consistent reisolation of Pythium ultimum was morphologically and molecularly confirmed from the diseased seedlings, thus fulfilling Koch's postulates. Pythium spp identification is prerequisite to develop effective management of pre and post-emergence damping-off. Pythium ultimum was previously reported in Nebraska to cause sugar beet seed rot and pre-emergence damping-off (Harvenson 2006). To our knowledge, this is the first report of Pythium ultimum causing damping-off on sugar beet in the Sidney factory district in Montana.

HomePlant DiseaseVol. 104, No. 2First Report of Alternaria Leaf Spot Caused by Alternaria tenuissima on Sugar Beet (Beta vulgaris) in Minnesota, U.S.A. PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Alternaria Leaf Spot Caused by Alternaria tenuissima on Sugar Beet (Beta vulgaris) in Minnesota, U.S.A.M. F. R. Khan, M. E. Haque, M. Bloomquist, M. Z. R. Bhuiyan, R. Brueggeman, S. Zhong, R. Sharma Poudel, T. Gross, P. Hakk, Y. Leng, and Y. LiuM. F. R. Khan†Corresponding author: M. F. R. Khan; E-mail Address: mohamed.khan@ndsu.eduhttp://orcid.org/0000-0001-5294-8651Department of Plant Pathology, North Dakota State University, Fargo, ND 58108Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108 , M. E. HaqueDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108, M. BloomquistSouthern Minnesota Beet Sugar Cooperative, Renville, MN 56284, M. Z. R. BhuiyanDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108, R. BrueggemanDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108, S. Zhonghttp://orcid.org/0000-0003-1928-0877Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, R. Sharma PoudelDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108, T. GrossDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108, P. HakkDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108, Y. LengDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108, and Y. LiuDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108 AffiliationsAuthors and Affiliations M. F. R. Khan1 2 † M. E. Haque1 M. Bloomquist3 M. Z. R. Bhuiyan1 R. Brueggeman1 S. Zhong1 R. Sharma Poudel1 T. Gross1 P. Hakk1 Y. Leng1 Y. Liu1 1Department of Plant Pathology, North Dakota State University, Fargo, ND 58108 2Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108 3Southern Minnesota Beet Sugar Cooperative, Renville, MN 56284 Published Online:9 Dec 2019https://doi.org/10.1094/PDIS-03-19-0603-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Minnesota is the top sugar beet (Beta vulgaris L.) producing state in the United States. In September 2018, foliar symptoms were first observed on older sugar beet leaves in about 3% of the cultivars in a coded variety trial in Renville (N 44.78, W –95.15), Minnesota. Symptoms were dark brown circular or irregular spots on healthy plants. Initially, the lesions were confined within distinct parallel veins of the leaves but eventually expanded and coalesced across veins. In severely affected plants, the entire symptomatic leaves died. Small square pieces (5 mm2) from the margin of lesions were excised with a sterile scalpel, surface sterilized with 70% ethanol for 1 min, rinsed thrice with sterile distilled water, air dried, transferred to potato dextrose agar, and incubated at 25°C with a 12-h photoperiod for 7 days. A colony that had white-brown velvety mycelia grew on the medium. Suspect isolates were further purified using a single-spore isolation method (Choi et al. 1999). Isolates were the same morphologically. Conidia were club-shaped, four to seven transverse septa, one to three longitudinal septa, and pale brown, with a beak-like apical cell, often in long chains or solitary. Conidia dimensions were 28 to 54 × 4.5 to 6 µm, and beaks when present were 2 to 4 µm (Kou et al. 2014). Based on the morphological characters, the fungus was tentatively identified as Alternaria species (Simmons 2007; Woudenberg et al. 2015). Fungal genomic DNA was extracted from two representative isolates using a Qiagen kit followed by PCR amplification with internal transcribed spacer (ITS) ITS 1/ITS 4 primers. The amplified PCR products were cleaned and sent for Sanger sequencing by GenScript (Piscataway, NJ). Isolates 1422F (GenBank accession MK611645) and 1424F (MK611649) had 98 and 100% sequence identity with Alternaria tenuissima (GenBank accessions MF373440 and MH374277), respectively (Ziedan et al. 2018). Pathogenicity testing was conducted by spraying a conidial suspension (5 × 105 conidia/ml) onto 14-leaf growth stage sugar beet plants (Crystal Beet Seed proprietary material). Mock-inoculated plants were sprayed with autoclaved water as a control. Plants were kept at 25°C and 75 to 85% relative humidity in a humidity chamber for 7 days and then transferred to a greenhouse kept at 23 ± 2°C and a 12-h photoperiod. Plants were watered daily. The experiment was done twice with four replicates and 10 plants per replicate. Two weeks postinoculation, about 30% of the inoculated leaves were infected and started to display irregular to circular lesions as observed in the field. No symptoms were observed on the control plants. The fungus was reisolated from diseased leaf tissues as described above, and macroscopic and microscopic analysis indicated the similar white-brown colony morphology and conidial structure, respectively. Genomic DNA was extracted from a single isolate as described above. Molecular detection performed using the same primers further confirmed that the isolate (MN384262) was 100% similar to A. tenuissima (GenBank accession MK611651). A. tenuissima has the potential to become a problem if susceptible varieties are grown over large production areas. Alternaria leaf spot on sugar beet has been reported in California (French 1989) and Michigan (Rosenzweig et al. 2019), where the disease has been associated with economic loss since 2015. To our knowledge, this is the first report of A. tenuissima causing leaf spot disease on sugar beet in Minnesota, U.S.A.The author(s) declare no conflict of interest.References:Choi, Y. W., et al. 1999. Fungal Diversity 3:29. https://www.fungaldiversity.org/fdp/sfdp/FD_3_29-38.pdf Google ScholarFrench, A. M. 1989. California Plant Disease Host Index. Department of Food and Agriculture, Sacramento, CA. Google ScholarKou, L. P., et al. 2014. Plant Dis. 98:690. https://doi.org/10.1094/PDIS-07-13-0802-PDN Abstract, Google ScholarRosenzweig, N., et al. 2019. Plant Dis. 103:2263. https://doi.org/10.1094/PDIS-12-18-2282-RE Link, ISI, Google ScholarSimmons, E. G. 2007. Alternaria: An Identification Manual. CBS Biodiversity Center, Utrecht, The Netherlands. Google ScholarWoudenberg, J. H. C., et al. 2015. Stud. Mycol. 82:1. https://doi.org/10.1016/j.simyco.2015.07.001 Crossref, ISI, Google ScholarZiedan, E. S. H., et al. 2018. J. Plant Prot. Res. 58:362. https://doi.org/10.24425/jppr.2018.124650 Google ScholarThe author(s) declare no conflict of interest.Funding: Funding was provided by Sugarbeet Research and Education Board of Minnesota and North Dakota.DetailsFiguresLiterature CitedRelated Vol. 104, No. 2 February 2020SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionSymptom of maize ear rot caused by Fusarium sporotrichioides (B. B. Wang et al.). Photo credit: C. X. Duan. Systemic symptoms of alfalfa mosaic virus (AMV) isolate CaM on leaves of potato (X. Z. Nie et al.). Photo credit: X. Z. Nie. Metrics Downloaded 3,551 times Article History Issue Date: 31 Jan 2020Published: 9 Dec 2019First Look: 3 Oct 2019Accepted: 30 Sep 2019 Pages: 580-580 Information© 2020 The American Phytopathological SocietyFundingSugarbeet Research and Education Board of Minnesota and North DakotaKeywordsfungivegetablesdisease managementcultivar/resistancepathogen detectionThe author(s) declare no conflict of interest.

HomePlant DiseaseVol. 103, No. 12First Report of Geotrichum candidum Causing Postharvest Rot of Sugar Beet (Beta vulgaris) Roots in Minnesota and North Dakota PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Geotrichum candidum Causing Postharvest Rot of Sugar Beet (Beta vulgaris) Roots in Minnesota and North DakotaM. F. R. Khan, M. E. Haque, R. Brueggeman, S. Zhong, M. Z. R. Bhuiyan, R. S. Poudel, T. Gross, P. Hakk, and Y. LiuM. F. R. Khan†Corresponding author: M. F. R. Khan; E-mail Address: Mohamed.khan@ndsu.eduhttp://orcid.org/0000-0001-5294-8651Department of Plant Pathology, North Dakota State University, Fargo, ND 58108Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108Search for more papers by this author, M. E. HaqueDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108Search for more papers by this author, R. BrueggemanDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108Search for more papers by this author, S. Zhonghttp://orcid.org/0000-0003-1928-0877Department of Plant Pathology, North Dakota State University, Fargo, ND 58108Search for more papers by this author, M. Z. R. BhuiyanDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108Search for more papers by this author, R. S. PoudelDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108Search for more papers by this author, T. GrossDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108Search for more papers by this author, P. HakkDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108Search for more papers by this author, and Y. LiuDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58108Search for more papers by this authorAffiliationsAuthors and Affiliations M. F. R. Khan1 2 † M. E. Haque1 R. Brueggeman1 S. Zhong1 M. Z. R. Bhuiyan1 R. S. Poudel1 T. Gross1 P. Hakk1 Y. Liu1 1Department of Plant Pathology, North Dakota State University, Fargo, ND 58108 2Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108 Published Online:14 Oct 2019https://doi.org/10.1094/PDIS-05-19-1000-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Minnesota (MN) and North Dakota (ND) together produce about 57% of U.S. sugar beets (Beta vulgaris L.) for sucrose extraction from its tap root. In October 2018, healthy sugar beet roots were harvested from two major production areas, Grand Forks, ND, and near Foxhome, MN, and kept in storage at 8°C and 80% relative humidity. After 1 week, water-soaked soft rot with brown irregular lesions 10 to 50 mm in diameter and thick foamy white mycelial growth were observed on the sugar beet roots, along with a smell of fermentation. About 10% of the roots from Grand Forks, ND, and 5% of the roots from Foxhome, MN, had symptoms that covered approximately 30% of the root surface. Small pieces (10 mm2) of lesion margins were excised, surface sterilized with 10% sodium hypochlorite for 1 min, rinsed twice with sterile distilled water, air dried, and transferred to corn meal agar (CMA) and clarified V8 and incubated at 25°C with a 12-h photoperiod for 7 days. Colonies were white, thin, flat, and feathery on both media. Hyphae were dichotomously branched and septate. Conidia were arthrosporous, terminal or intercalary, hyaline, subglobose, one-celled, often in chains and/or solitary. The dimension of conidia varied from 5 to 12 × 2 to 5 µm (Watanabe 2002). Based on cultural and morphological characteristics, the fungus was tentatively identified as Geotrichum species. Genomic DNA was extracted (Norgen Biotek Corp., cat. no. 27300) from eight isolates: four isolates each from ND and MN. The isolates from each state were identical. To confirm the identity of the fungus, the universal internal transcribed spacer (ITS) region was amplified using the ITS1/ITS4 primers (White et al. 1990). The amplified PCR products were cleaned and sent for Sanger sequencing to GenScript. The sequences for the ITS-5.8S rDNA region for the ND (GenBank accession MK436200) isolates had 99% sequence identity with G. candidum accessions JQ668739, KY103456, and KR815826. For the same genetic region, the MN (MK436203) isolates had 99% sequence identity with G. candidum accessions KF112070 and LC054542. In comparison with the G. candidum type strain CBS 178.71 (KF984491), the ND and MN isolates had 95 and 91% sequence identity, respectively. Pathogenicity was confirmed in the greenhouse. Twelve 20-week-old healthy sugar beet (cv. Crystal 101) roots were surface sterilized and scraped with a sterile cork borer, followed by plugging the wound (5 mm2) with 7-day-old G. candidum on CMA. Mock-inoculated sugar beet roots (12) were used as a control. All the roots were kept at 25°C and 80% relative humidity. One week postinoculation, all inoculated sugar beet roots had the same symptoms as the field-infected roots. No symptoms were observed in the mock treatment. The fungus reisolated from the diseased beet root had identical cultural and morphological characteristics to G. candidum. There are several reports of G. candidum as the causal agent for rot of fruits, including Mori fructus and peach, as well as storage rots of sweet potato (Alam et al. 2017; Holmes et al. 2002; Zhang et al. 2018). Root rot of sugar beet caused by Geotrichum sp. F373 was reported for roots collected from Oregon and Idaho (Strausbaugh et al. 2009). To our knowledge, this is the first report of G. candidum causing rot on sugar beet root in storage in ND and MN, U.S.A. Because roots may be stored for about 4 to 5 months in nonventilated piles before processing, it will be useful to investigate and develop strategies to limit losses that could be caused by G. candidum.The author(s) declare no conflict of interest.References:Alam, M. W., et al. 2017. Plant Dis. 101:1543. https://doi.org/10.1094/PDIS-01-17-0121-PDN Abstract, Google ScholarHolmes, G. J., et al. 2002. Plant Dis. 86:695. https://doi.org/10.1094/PDIS.2002.86.6.695C Link, Google ScholarStrausbaugh, C. A., et al. 2009. Can. J. Plant Pathol. 31:232. https://doi.org/10.1080/07060660909507596 Crossref, ISI, Google ScholarWatanabe, T. 2002. Page 278 in Pictorial Atlas of Soil and Seed Fungi: Morphologies of Cultured Fungi and Keys to Species, 2nd Ed. CRC Press, Boca Raton, FL. Crossref, Google ScholarWhite, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. Crossref, Google ScholarZhang, L., et al. 2018. Plant Dis. 102:2640. https://doi.org/10.1094/PDIS-03-18-0536-PDN Link, Google ScholarThe author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Vol. 103, No. 12 December 2019SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionChlorotic symptom of Paris polyphylla var. yunnanensis infected by PMMoV-QJ (Wen et al.). Photo credit: M. F. Zhao. Symptoms of Puccinia triticina on wheat (Brar et al.). Photo credit: G. S. Brar. Metrics Article History Issue Date: 21 Nov 2019Published: 14 Oct 2019First Look: 5 Aug 2019Accepted: 2 Aug 2019 Pages: 3278-3278 Information© 2019 The American Phytopathological SocietyKeywordsfungivegetablesdisease managementpathogen detectionThe author(s) declare no conflict of interest.Cited byFirst Report of Geotrichum candidum Causing Postharvest Sour Rot on Kiwifruits in ChinaHao Cheng, Wei Tang, Hanyang Wang, Qianwen Liu, Huanhuan Li, and Yongsheng Liu7 April 2021 | Plant Disease, Vol. 105, No. 5Konya İlinde Yetiştirilen Patates Yumrularında Lastik Çürüklük Hastalık Etmeni Geotrichum candidum’un İzolasyonu, Morfolojik ve Moleküler Karakterizasyonu13 August 2020 | Kahramanmaraş Sütçü İmam Üniversitesi Tarım ve Doğa DergisiRetracted : First report of Talaromyces pinophilus causing postharvest rot of sugar beet ( Beta vulgaris ) in Minnesota, USA12 November 2020 | New Disease Reports, Vol. 42, No. 1

HomePlant DiseaseVol. 104, No. 4First Report of Sclerotinia sclerotiorum Causing Leaf Blight in Sugar Beet (Beta vulgaris) in North Dakota, U.S.A. PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Sclerotinia sclerotiorum Causing Leaf Blight in Sugar Beet (Beta vulgaris) in North Dakota, U.S.A.M. F. R. Khan, M. Z. R. Bhuiyan, K. Chittem, F. Shahoveisi, M. E. Haque, Y. Liu, P. Hakk, S. Solanki, L. E. del Rio, and G. LaPlanteM. F. R. Khan†Corresponding author: M. F. R. Khan; E-mail Address: Mohamed.khan@ndsu.eduhttp://orcid.org/0000-0001-5294-8651Department of Plant Pathology, North Dakota State University, Fargo, ND 58102University of Minnesota, St. Paul, MN 55108Search for more papers by this author, M. Z. R. BhuiyanDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58102Search for more papers by this author, K. ChittemDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58102Search for more papers by this author, F. ShahoveisiDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58102Search for more papers by this author, M. E. HaqueDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58102Search for more papers by this author, Y. LiuDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58102Search for more papers by this author, P. HakkDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58102Search for more papers by this author, S. SolankiDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58102Search for more papers by this author, L. E. del RioDepartment of Plant Pathology, North Dakota State University, Fargo, ND 58102Search for more papers by this author, and G. LaPlanteGL Crop Consulting, Wahpeton, ND 58075Search for more papers by this author AffiliationsAuthors and Affiliations M. F. R. Khan1 2 † M. Z. R. Bhuiyan1 K. Chittem1 F. Shahoveisi1 M. E. Haque1 Y. Liu1 P. Hakk1 S. Solanki1 L. E. del Rio1 G. LaPlante3 1Department of Plant Pathology, North Dakota State University, Fargo, ND 58102 2University of Minnesota, St. Paul, MN 55108 3GL Crop Consulting, Wahpeton, ND 58075 Published Online:12 Feb 2020https://doi.org/10.1094/PDIS-11-19-2304-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Sugar beet (Beta vulgaris L.) is an economically important crop in North Dakota. In July 2019, light brown to black necrotic leaf lesions with grayish centers were observed on commercial sugar beet plants in Fairmount, North Dakota (46.054° N; 96.602° W). The disease was present in about 2% of plants and affected on average 40% of leaf tissues. Affected leaves were collected, surface disinfested in 70% ethanol for 1 min, rinsed three times in deionized water, and air dried in a laminar flow hood. Leaf pieces containing the edges of infected tissues were plated on dishes containing potato dextrose agar (PDA) and incubated in dark for 48 h at 25°C. Whitish, cottony mycelium were transferred into PDA plates for 10 days to obtain pure cultures. The pure cultures developed black sclerotia around the edge of the dishes. Sclerotia were hard with a blackish external appearance, globose to irregular shaped, and were 4.8 to 5.2 mm in length. Based on colony and sclerotial morphology, the cultures were putatively identified as Sclerotinia sclerotiorum (Kohn 1979). Genomic DNA was extracted from mycelium of two representative isolates, NDSB1 and NDSB2, using the Qiagen DNeasy Plant mini kit and subjected to a multiplex PCR assay that distinguishes four Sclerotinia species (Abd-Elmagid et al. 2013). A ≈170-bp amplicon was observed on a 1% agarose gel stained with ethidium bromide, confirming the identity of the isolates as S. sclerotiorum. The internal transcribed spacer-5.8S rDNA region was amplified using the ITS1/ITS4 primers (White et al. 1990). The nucleotide sequences of the 518-bp amplicons produced by NDSB1 and NDSB2 were 100% identical, so the nucleotide sequence of only one isolate was deposited in NCBI GenBank as NDSB1 (MN525565). The amplicon had 100% sequence identity with a number of S. sclerotiorum GenBank accessions (e.g., CP017820 and KY859158). Koch’s postulates were fulfilled using the same two North Dakota isolates (NDSB1 and NDSB2) to inoculate six-leaf growth stage sugar beet plants (Maribo 504). Four plants, one per replicate, were inoculated by placing a 1-cm agar plug with actively growing hyphal tips from a 48-h-old colony of S. sclerotiorum on a leaf. In each replicate, a second plant had an agar plug with no hyphae placed on a leaf. All plants were incubated in a misting chamber at 28°C for 48 h with 10 h of light daily, after which light brown necrotic lesions similar to field samples were observed. Mock-inoculated plants did not develop lesions. Isolations from infected tissues were morphologically identical to the ones retrieved from field plants. This is the first report of S. sclerotiorum infecting leaves on sugar beet in North Dakota, U.S.A. This report highlights the increased risk this disease represents to the sugar beet industry, especially because crops of economic importance, such as soybean and edible beans, are hosts of this pathogen and are typically planted in rotation with sugar beet.The author(s) declare no conflict of interest.References:Abd-Elmagid, A., et al. 2013. J. Microbiol. Methods 92:293. https://doi.org/10.1016/j.mimet.2012.12.020 Crossref, ISI, Google ScholarKohn, L. M. 1979. Phytopathology 69:881. https://doi.org/10.1094/Phyto-69-881 Crossref, ISI, Google ScholarWhite, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. Crossref, Google ScholarThe author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Vol. 104, No. 4 April 2020SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionDisease symptoms of leaves of the peach cultivar Royal Bell caused by Xanthomonas arboricola pv. pruni (R. Iličić and T. Popović). Photo credit: R. Iličić. Symptoms of chilli yellow ringspot virus on a chilli pepper plant (K. Y. Zheng et al.). Photo credit: J. H. Dong. Metrics Downloaded 1,717 times Article History Issue Date: 3 Apr 2020Published: 12 Feb 2020First Look: 17 Dec 2019Accepted: 15 Dec 2019 Pages: 1258-1258 Information© 2020 The American Phytopathological SocietyKeywordsfungivegetablesdisease managementpathogen diversityThe author(s) declare no conflict of interest.Cited ByFirst Report of Leaf Blight of Sugar Beet (Beta vulgaris) Caused by Sclerotinia sclerotiorum in Minnesota, U.S.A.Mohamed F. R. Khan, Md. Ziaur Rahman Bhuiyan, Yangxi Liu, Dilip Lakshman, and Mark Bloomquist19 July 2021 | Plant Health Progress, Vol. 22, No. 2Analysis and Identification of QTL for Resistance to Sclerotinia sclerotiorum in Pea (Pisum sativum L.)19 November 2020 | Frontiers in Genetics, Vol. 11