Leptosphaeria maculans
black leg of crucifers, stem canker
Phoma brassicae, Phoma lingam, Phoma
oleracea, Phoma napobrassicae, Phyllosticta brassicae, Phyllosticta napi Sacc., Plenodomus lingam,
Pleospora maculans, Sphaeria lingam, Sphaeria
maculans
Worldwide
CA, GA, HI, ID, IL, KY, NY, ND, OK, OR, WA, WI
2025-10-14
fungus
China, Korea
Restricted to Brassicaceae
LEPTMA
Leptosphaeria maculans is a fungus that causes black leg disease in canola and other cruciferous crops. It spreads mainly through windborne ascospores from infected plant residues, which can travel several kilometers to infect young plants. Rain and humidity trigger spore release and infection. The fungus is also seedborne and can cause early infections in seedlings, especially under humid or crowded conditions.
4 Known Hosts
Brassica napus
rapeseed
Yes
CABI CPC, LEPTMA-2, LEPTMA-3, LEPTMA-4
Seed transmission of this pathogen is well established and accepted by the seed industry
Yes
Blotter paper
This test has been validated by the ISTA and NSHS
Blotter paper is the standard method of the NSHS
NSHS USDA, ISTA
Chemical, Cultural
Control relies on crop rotation, resistant cultivars, disease-free seed, and fungicide treatments to limit infection from residues and seed.
CABI CPC, McGEE
2025-10-14 15:21:10
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Fitt BDL, Hu BC, Li ZQ, Liu SY, Lange RM, Kharbanda PD, Butterworth MH, White RP. 2008. Strategies to prevent spread of Leptosphaeria maculans (phoma stem canker) onto oilseed rape crops in China; costs and benefits. Plant Pathol. 57:652–664.
Janowski, K. M. (2021). Understanding the Epidemiology and Genetic Diversity of Leptosphaeria maculans, and Exploring Chemical Control Strategies to Manage Blackleg of Winter Canola (Brassica napus) in Northern Idaho (Master's thesis, University of Idaho).
Gabrielson, R.L. (1983). Black leg disease of crucifers caused by Leptosphaeria maculans (Phoma lingam) and its control. Seed Science and Technology 11:749-780.
United Stated Department of Agriculture, Animal and Plant Health Protection Service National Seed Health System (USDA-APHIS NSHS) www.seedhealth.org
International Rules for Seed Testing. International Seed Testing Association; www.seedtest.org
McGee, DC. 1988, Maize Diseases; A reference source for Seed Technoligists. American Phytopathological Society, St. Paul, MN USA
Brassica oleracea vars.
cabbage, cauliflower, broccoli, brussel sprout
Yes
LEPTMA-8, LEPTMA-12, CABI CPC, LEPTMA-2, LEPTMA-3, LEPTMA-4, LEPTMA-5
Seed transmission of this pathogen is well established and accepted by the seed industry
Yes
Blotter paper
This test has been validated by the ISTA and the NSHS
Blotter paper is the standard method of the NSHS
NSHS USDA, ISTA
Chemical, cultural
Control relies on crop rotation, resistant cultivars, disease-free seed, and fungicide treatments to limit infection from residues and seed.
CABI CPC, McGEE
2025-10-14 16:39:40
Jacobsen BJ, Williams PH, 1971. Histology and control of Brassica oleracea seed infection by Phoma lingam. Plant Disease Rprt 55:934-938.
Gabrielson RL, 1983. Blackleg disease of cabbage caused by Leptosphaeria maculans (Phoma lingam) and its control. Seed Science Technology, 11:749.
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Fitt BDL, Hu BC, Li ZQ, Liu SY, Lange RM, Kharbanda PD, Butterworth MH, White RP. 2008. Strategies to prevent spread of Leptosphaeria maculans (phoma stem canker) onto oilseed rape crops in China; costs and benefits. Plant Pathol. 57:652–664.
Janowski, K. M. (2021). Understanding the Epidemiology and Genetic Diversity of Leptosphaeria maculans, and Exploring Chemical Control Strategies to Manage Blackleg of Winter Canola (Brassica napus) in Northern Idaho (Master's thesis, University of Idaho).
Gabrielson, R.L. (1983). Black leg disease of crucifers caused by Leptosphaeria maculans (Phoma lingam) and its control. Seed Science and Technology 11:749-780.
Bilodeau, J.G., Tropiano, R. and Briere, S.C. (2012). Development of diagnostic assays for detection of Verticillium in alfalfa and flax and detection of blackleg (Leptosphaeria maculans) in canola using real-time PCR. Phytopathology 102(7) (SUPPLEMENT) July 2012.
United Stated Department of Agriculture, Animal and Plant Health Protection Service National Seed Health System (USDA-APHIS NSHS) www.seedhealth.org
International Rules for Seed Testing. International Seed Testing Association; www.seedtest.org
McGee, DC. 1988, Maize Diseases; A reference source for Seed Technoligists. American Phytopathological Society, St. Paul, MN USA
Brassica rapa
turnip, chinese cabbage
Yes
LEPTMA-8, CABI CPC, LEPTMA-2, LEPTMA-3, LEPTMA-4
Seed transmission of this pathogen is well established and accepted by the seed industry
Yes
Blotter paper
This test has been validated by the ISTA and NSHS
Blotter paper is the standard method of the NSHS
NSHS USDA, ISTA
chemical, Cultural
Control relies on crop rotation, resistant cultivars, disease-free seed, and fungicide treatments to limit infection from residues and seed.
CABI CPC, McGEE
2025-10-14 16:41:32
Jacobsen BJ, Williams PH, 1971. Histology and control of Brassica oleracea seed infection by Phoma lingam. Plant Disease Rprt 55:934-938.
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Fitt BDL, Hu BC, Li ZQ, Liu SY, Lange RM, Kharbanda PD, Butterworth MH, White RP. 2008. Strategies to prevent spread of Leptosphaeria maculans (phoma stem canker) onto oilseed rape crops in China; costs and benefits. Plant Pathol. 57:652–664.
Janowski, K. M. (2021). Understanding the Epidemiology and Genetic Diversity of Leptosphaeria maculans, and Exploring Chemical Control Strategies to Manage Blackleg of Winter Canola (Brassica napus) in Northern Idaho (Master's thesis, University of Idaho).
Gabrielson, R.L. (1983). Black leg disease of crucifers caused by Leptosphaeria maculans (Phoma lingam) and its control. Seed Science and Technology 11:749-780.
United Stated Department of Agriculture, Animal and Plant Health Protection Service National Seed Health System (USDA-APHIS NSHS) www.seedhealth.org
International Rules for Seed Testing. International Seed Testing Association; www.seedtest.org
McGee, DC. 1988, Maize Diseases; A reference source for Seed Technoligists. American Phytopathological Society, St. Paul, MN USA
Raphanus sativus
radish
Yes
LEPTMA-8, LEPTMA-9, CABI CPC, LEPTMA-2, LEPTMA-3, LEPTMA-4, LEPTMA-5
Seed transmission of this pathogen is well established and accepted by the seed industry
Yes
Blotter paper
This test has been validated by the ISTA and NSHS
Blotter paper is the standard method of the NSHS
NSHS USDA, ISTA
chemical, cultural
Control relies on crop rotation, resistant cultivars, disease-free seed, and fungicide treatments to limit infection from residues and seed.
CABI CPC, McGEE
2025-10-14 16:42:10
Jacobsen BJ, Williams PH, 1971. Histology and control of Brassica oleracea seed infection by Phoma lingam. Plant Disease Rprt 55:934-938.
Mannerucci GF, Gambogi P, Vannacci G, 1982. Detection of pathogenic fungi on seeds of market garden plants. Informatore Fitopatologico, 32:47-54
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Fitt BDL, Hu BC, Li ZQ, Liu SY, Lange RM, Kharbanda PD, Butterworth MH, White RP. 2008. Strategies to prevent spread of Leptosphaeria maculans (phoma stem canker) onto oilseed rape crops in China; costs and benefits. Plant Pathol. 57:652–664.
Janowski, K. M. (2021). Understanding the Epidemiology and Genetic Diversity of Leptosphaeria maculans, and Exploring Chemical Control Strategies to Manage Blackleg of Winter Canola (Brassica napus) in Northern Idaho (Master's thesis, University of Idaho).
Gabrielson, R.L. (1983). Black leg disease of crucifers caused by Leptosphaeria maculans (Phoma lingam) and its control. Seed Science and Technology 11:749-780.
Bilodeau, J.G., Tropiano, R. and Briere, S.C. (2012). Development of diagnostic assays for detection of Verticillium in alfalfa and flax and detection of blackleg (Leptosphaeria maculans) in canola using real-time PCR. Phytopathology 102(7) (SUPPLEMENT) July 2012.
United Stated Department of Agriculture, Animal and Plant Health Protection Service National Seed Health System (USDA-APHIS NSHS) www.seedhealth.org
International Rules for Seed Testing. International Seed Testing Association; www.seedtest.org
McGee, DC. 1988, Maize Diseases; A reference source for Seed Technoligists. American Phytopathological Society, St. Paul, MN USA
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