Xanthomonas hortorum pv. carotae
bacterial blight of carrot
Bacterium carotae, Phytomonas carotae, Pseudomonas carotae, Xanthomonas campestris pv. carotae, Xanthomonas carotae
Africa: Mauritius, South Africa; Asia: Japan, Kazakhstan, South Korea, Turkey; Europe: Germany, Italy, Poland, Russia, Spain; North America: Canada, USA; Oceania: Australia; South America: Brazil.
AZ, CA, ID, IN, IA, NM, NY, OR, WA, WI
2025-12-10
bacterium
Mexico
Main: carrot, coriander
XANTCR
Xanthomonas hortorum pv. carotae is a bacterial pathogen that causes leaf blight in carrots, characterized by water-soaked leaf lesions and yellowing, which can reduce yield and quality. The bacteria can be transmitted through contaminated seed, irrigation water, tools, and infected plant debris. Warm, wet conditions favor disease development and spread.
Crops
Coriandrum sativum
coriander
Uncertain
XANTCR-6, CABI CPC
Seed as a pathway for this crop is uncertain. A single reference lists seed as a possible pathway, but no supporting data are presented, and the report does not cite evidence; seed transmission can only be inferred.
The standard seed wash protocol for carrot seed may be used in some laboratories, but no references found indicating this method works for coriander.
2025-12-10 16:38:54
Daucus carota
carrot
Yes
XANTCR-2, XANTCR-3, XANTCR-4, XANTCR-5, XANTCR-8, XANTCR-9, XANTCR-10, XANTCR-11, XANTCR-12, XANTCR-14, XANTCR-15, XANTCR-16, XANTCR-17, XANTCR-18
Seed as a pathway well established and accepted. Populations of bacteria in seed samples must be high to cause disease losses.
Yes
Seed wash, PCR
NSHS: METHOD: Rb 1.1 ISTA seed wash and plating method 7-020: ver 1.4, 2022; SUBMITTED BY: plating assay adapted from ISTA Method 7-020, ver 1.4, 2022; qPCR assay by the U.S. ISHI Veg committee
METHOD: Rb 1.1
NSHS USDA, ISHI-ISF
Chemical, cultural
Hot water seed treatment. Use disease-free seed, crop rotations, and plowing down debris.
XANTCR-4, XANTCR-8, CABI CPC, XANTCR-13
2025-12-10 16:20:38
Chupp Ch, Sherf AF, 1960. Vegetable diseases and their control. New York, USA: The Ronald Press Company
Kuan T-L, Minsavage GV, Gabrielson RL, 1985. Detection of Xanthomonas campestris pv. carota in carrot seed. Plant Disease, 69:758-760
Ark PA, Gardner MW, 1944. Carrot bacterial blight as it affects the roots. Phytopathology, 34:415-420
Umesh K, Davis R, Gilbertson R, 1996. Seed contamination thresholds associated with occurrence of bacterial blight of carrots and development of a DNA based detection method for Xanthomonas campestris pv. carotae. Phytopathology, 86: S11
International Seed Federation Regulated Pest List Database. pestlist.worldseed.org Nyon Switzerland
Crowe, F. and Bafus, R. (2003). Evaluation of the potential for systemic infection of carrot seed crops by Xanthomonas campestris pv. carotae. Pp. 1-3 in Central Oregon Agricultural Research Center Annual Reports, Special Report 1046, Agricultural Research Station, Oregon State University.
Du Toit, L.J., Crowe, F.J., Derie, M.L., Simmons, R.B. and Pelter, G.Q. (2005). Bacterial blight in carrot seed crops in the Pacific Northwest. Plant Disease 89: 896-907.
Kimbrel J.A., Givan, S.A., Temple, T.N., Johnson, K.B. and Chang, J.H. (2011). Genome sequencing and comparative analysis of the carrot bacterial blight pathogen, Xanthomonas hortorum pv. carotae M081, for insights into pathogenicity and applications in molecular diagnostics. Molecular Plant Pathology 12(6): 580-94.
Nega, E., Ulrich, R., Werner, S. and Jahn, M. (2003). Hot water treatment of vegetable seed an alternative seed treatment method to control seed borne pathogens in organic farming. Journal of Plant Diseases and Protection 110(3): 220-234.
Christianson, C. E., Jones, S. S., & du Toit, L. J. (2015). Screening carrot germplasm for resistance to Xanthomonas hortorum pv. carotae. HortScience, 50(3), 341-350.
Myung, I.S., Yoon, M.J., Lee, J.Y., Kim, G.D., Lee, M.H., Hwang, E.Y., Shim, H.S., 2014. First report of bacterial leaf blight of carrot caused by Xanthomonas hortorum pv. carotae in Korea.Plant Disease, 98(2) 275-276.
Scott, J.C., Dung, J.K.S., 2020. Distribution of Xanthomonas hortorum pv. carotae populations in naturally infested carrot seed lots.Plant Disease, 104(8) 2144-2148.
Toit, L.J. du, Derie, M.L., Christianson, C.E., Hoagland, L., Simon, P., 2014. First report of bacterial blight of carrot in Indiana caused by Xanthomonas hortorum pv. carotae. Plant disease, 98(5) 685.
Toit, L.J. du, Schaad, N.W., Gilbertson, R.L., 2017. Detection of Xanthomonas hortorum pv. carotae in carrot seed. In: Detection of Plant-Pathogenic Bacteria in Seed and Other Planting Material, Second Edition [ed. by Fatmi, M., Walcott, R.R., Schaad, N.W.].
United Stated Department of Agriculture, Animal and Plant Health Protection Service National Seed Health System (USDA-APHIS NSHS) www.seedhealth.org
ISHI Seed Health Test Methods - https://worldseed.org/resources/ishi-methods/
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Temple, L.T.N., du Toit, L.J., Derie, M.L. and Johnson, K.B. (2013). Quantitative molecular detection of Xanthomonas hortorum pv. carotae in carrot seed before and after hot-water treatment. Plant Disease 97: 1585-1592.
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