Didymella lycopersici
canker of tomato
Ascochyta lycopersici, Diplodina lycopersici, Phoma lycopersici, Sphaeronaema lycopersici,
Africa: Cote d'Ivorie, Morocco, Nigeria, Togo, Uganda; Asia: Armenia, Azerbaijan, Brunei, China, India, Israel, Japan, Jordan, Malaysia; Europe: Albania, Austria, Belarus, Belgium, Bulgaria, Cyprus, Denmark, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Lithuania, Moldova, Netherlands, Norway, Poland, Portugal, Romania, Spain, Sweden, Ukraine, UK; North America: Barbados, Canada, Cuba, Dominican Republic, Haiti, Mexico, Panama, Puerto Rico, Trinidad and Tobago, USA; Oceania: French Polynesia, New Caledonia, New Zealand, Papua New Guinea, Tonga; South America: Brazil, Venezuela.
AK, DE, FL, NJ, NC, OR, VA, WI
2025-07-22
fungus
China, Korea, Thailand
Main: tomato; Other: pepper, eggplant, potato
DIDYLY
Didymella lycopersici is a fungus that causes stem rot in tomatoes. It survives in soil, plant debris, seeds, and on weeds like nightshade. The disease primarily spreads in cool, wet conditions, particularly with overhead watering. Older plants and poor soil nutrition make it worse. Though seed-borne it doesn’t always lead to infection.
3 Known Hosts
Capsicum annuum
pepper
uncertain
DIDYLY-8, DIDYLY-9
Pepper seed as a pathway is uncertain because the only evidence comes from a single study, which found the fungus in the seed coats and inner parts of one pepper variety, but the research was primarily done in a controlled environment. No other research has confirmed that this fungus spreads through pepper seeds.
2025-07-22 18:14:12
Khulbe RD, Dhyani AP, Sati MC, 1991. Seed-borne Didymella lycopersici and Diaporthe phaseolorum: their location in seed, transmission and pathogenic importance in red pepper and bell pepper. Indian Phytopathology, 44:480-486
Farr, D.F. and Rossman, A.Y. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. 2016, http://nt.ars-grin.gov/fungaldatabases/
Solanum lycopersicum
tomato
uncertain
DIDYLY-2, DIDYLY-3, DIDYLY-4, DIDYLY-7, DIDYLY-8, DIDYLY-9, CABI CPC, DIDYLY-10, DIDYLY-12, DIDYLY-13
It is uncertain whether Didymella lycopersici is transmitted through tomato seed, as the fungus has been found inside seed coats; however, seed-to-seedling transmission has occurred in controlled conditions and declines greatly over time. Field studies reveal minimal evidence of widespread infection from seed, with surface spores surviving for less than nine months and internal infections rarely persisting beyond 21 months, suggesting that seed is not a major pathway for disease spread. Instead it is spready by infected soil, plant debris, and weed hosts.
Yes
Agar plating, ELISA, PCR
This method has not been validated or standardized. Commercial testing is available.
DIDYLY-2, DIDYLY-3, DIDYLY-11, DIDYLY-13
chemical, cultural, mechanical
Use pathogen-free seed, crop rotation to reduce or eliminate inoculum, destruction of alternate hosts, and chemical treatments. Avoid overhead irrigation and have adequate ventilation in greenhouses.
DIDYLY-2, DIDYLY-4, DIDYLY-6, DIDYLY-7
2025-07-22 17:53:08
Knight DE, Keyworth WG, 1960. Didymella stem rot of outdoor tomatoes. I and II. Annals of Applied Biology, 48:245-269.
Phillips DH, 1956. Tomato seed transmission of Didymella lycopersici Kleb. Transactions of British Mycological Society, 39:319-329.
Fagg J, Fletcher JT, 1987. Studies of the epidemiology and control of tomato stem rot caused by Didymella lycopersici. Plant Pathology, 36:361-366
Kasselaki AM, Malathrakis NE, Goumas DE, Leifert C, 2007. Effect of alternative seed treatments on seed-borne fungal diseases in tomato. In: Improving sustainability in organic and low input food production systems. Proceedings of the 3rd International Congress of the European Integrated Project Quality Low Input Food (QLIF), University of Hohenheim, Germany, 20-23 March, 2007 [ed. by Niggli, U.\Leifert, C.\Alföldi, T.\Lück, L.\Willer, H.]. Frick, Switzerland: Research Institute of Organic Agriculture (FiBL), 289-291.
Khulbe RD, Dhyani AP, Sati MC, 1991. Seed-borne Didymella lycopersici and Diaporthe phaseolorum: their location in seed, transmission and pathogenic importance in red pepper and bell pepper. Indian Phytopathology, 44:480-486
Farr, D.F. and Rossman, A.Y. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. 2016, http://nt.ars-grin.gov/fungaldatabases/
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
FISHER), D. E. K. N., & Keyworth, W. G. (1960). DIDYMELLA STEM‐ROT OF OUTDOOR TOMATOES: I. STUDIES ON SOURCES OF INFECTION AND THEIR ELIMINATION. Annals of Applied Biology, 48(2), 245-258.
Maude, R.B., 1962. Seed transmission of Didymella stem-rot of tomatoes. Annals of Applied Biology, 50(1), pp.105-111.
Kokaeva, L., Chudinova, E., Berezov, A., Yarmeeva, M., Balabko, P., Belosokhov, A. and Elansky, S., 2020. Fungal diversity in tomato (Solanum lycopersicum) leaves and fruits in Russia. Journal of Central European Agriculture, 21(4), pp.809-816.
Kimani, E.W., 1990. Serological detection of Didymella lycopersici (Kleb.) Department of Plant Science. B. Sc. University of Nairobi. 81 pp.
Kasselaki AM, Malathrakis NE, Goumas DE, Cooper JM, Leifert C, 2008. Effect of alternative treatments on seed-borne Didymella lycopersici in tomato. Journal of Applied Microbiology, 105:36-41
Solanum melongena
eggplant
No
CABI CPC, ISF RPLD, EPPO
No references found indicating seed is a pathway. Seed pathway may be inferred because tomato seed is a pathway.
2025-07-22 17:47:56
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