Cladosporium cucumerinum
scab of cucurbits
Cladosporium cucumeris, Cladosporium scabies, Macrosporium cucumerinum, Macrosporium melophthorum, Scolicotrichum melophthorum
Africa: Kenya, Mauritius, Morocco, South Africa, Zambia, Zimbabwe; Asia: Azerbaijan, Bhutan, China, India, Iran, Israel, Japan, Lebanon, Pakistan, South Korea, Thailand, Turkey, Yemen; Europe: Austria, Belarus, Bulgaria, Cyprus, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Lithuania, Netherlands, Norway, Poland, Portugal, Romania, Russia, Sweden, UK; North America: Barbados, Canada, Cuba, El Salvador, Mexico, Panam, Puerto Rico, Trinidad and Tobago, USA; Oceania: French Polynesia; South America: Chile.
FL. ME, MI, NY, NC, OK, OR, TX, WA
2025-12-22
fungus
China
Main: cucumber; Other: pumpkin, gourd, melon, watermelon
CLADCU
Cladosporium cucumerinum is a fungal pathogen that causes scab disease primarily in cucurbits, especially cucumber. It survives on infected plant debris and spreads mainly through rain splash, irrigation water, and mechanical contact, infecting leaves, stems, and fruit under cool, moist conditions. Seed transmission has been suggested in early literature, but it is generally considered a minor or uncertain pathway compared with field-to-field spread via infected debris and splash dispersal. Infection occurs rapidly under wet conditions, with symptoms developing within days and new spores produced shortly thereafter, allowing quick disease buildup and spread.
Crops
Citrullus lanatus
watermelon
Uncertain
CLADCU-3, CLADCU-5, CABI CPC, CLADCU-10
Watermelon seed has been mentioned in older literature as a possible pathway for Cladosporium cucumerinum, primarily by inference rather than direct evidence. These references are not supported by demonstrated natural seed transmission, and no more recent studies have confirmed seed as a pathway; therefore, watermelon seed remains an uncertain pathway for this pathogen.
No
No test specific for C. lanatus was found. Freezing blotter has been used for Cucurbita spp.
Chemical, cultural
Use clean seed, rotate crops, and remove infected debris to reduce inoculum; seed testing or treatment may help limit potential seed-associated risk.
CABI CPC, CLADCU-10
2025-12-22 18:44:57
Zitter, T.A. Scab 2016. The American Phytopathologogical Society APSnetfeatures. (http://www.apsnet.org/publications/apsnetfeatures/Pages/Scab.aspx) St. Paul, MN
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.
Keinath, A. P., Wintermantel, W. M., & Zitter, T. A. (2017). Compendium of cucurbit diseases and Pests (No. Ed. 2, pp. 228-pp).
Cucumis melo
melon
Uncertain
CLADCU-3, CLADCU-5, CABI CPC, CLADCU-7, CLADCU-10
Melon seed has been mentioned in older literature as a possible pathway for Cladosporium cucumerinum, primarily by inference rather than direct evidence. These references are not supported by demonstrated natural seed transmission, and no more recent studies have confirmed seed as a pathway; therefore, melon seed remains an uncertain pathway for this pathogen.
no
No references found indicating a seed test exists for C. cucumerinum in melon seed.
Chemical, cultural
Use clean seed, rotate crops, and remove infected debris to reduce inoculum; seed testing or treatment may help limit potential seed-associated risk.
CABI CPC, CLADCU-10
2025-12-22 18:43:48
Zitter, T.A. Scab 2016. The American Phytopathologogical Society APSnetfeatures. (http://www.apsnet.org/publications/apsnetfeatures/Pages/Scab.aspx) St. Paul, MN
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.
Ellis, M.B. and Holliday, P., 1972. Cladosporium cucumerinum.[Descriptions of Fungi and Bacteria]. IMI Descriptions of Fungi and Bacteria, (35).
Keinath, A. P., Wintermantel, W. M., & Zitter, T. A. (2017). Compendium of cucurbit diseases and Pests (No. Ed. 2, pp. 228-pp).
Cucumis sativus
cucumber
Uncertain
CLADCU-3, CLADCU-5, CABI CPC, CLADCU-6, CLADCU-7, CLADCU-8, CLADCU-9, CLADCU-10, CLADCU-11, CLADCU-12
Cucumber seed has frequently been described in the literature as a possible pathway for Cladosporium cucumerinum, with multiple sources referring to the pathogen as “may be seedborne.” However, these references largely trace back to early or secondary citations, and no studies have clearly demonstrated or confirmed natural seed transmission under field conditions. As a result, cucumber seed as a pathway remains uncertain, and disease spread is considered to occur primarily via infected crop debris and airborne or mechanically dispersed conidia rather than through seed.
No
No references found indicating a seed test exists for C. cucumerinum in cucumber seed.
Chemical, cultural
Use clean seed, rotate crops, and remove infected debris to reduce inoculum; seed testing or treatment may help limit potential seed-associated risk.
CLADCU-8, CLADCU-9, CLADCU-10
2025-12-22 18:33:58
Zitter, T.A. Scab 2016. The American Phytopathologogical Society APSnetfeatures. (http://www.apsnet.org/publications/apsnetfeatures/Pages/Scab.aspx) St. Paul, MN
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.
LEAF, O.A., 1963. The Relation of Seed and Soil-borne Inoculum to the Epidemiology of Angular Leaf Spot of Cucumber in Wisconsin. The Plant Disease Reporter, 47:15
Ellis, M.B. and Holliday, P., 1972. Cladosporium cucumerinum.[Descriptions of Fungi and Bacteria]. IMI Descriptions of Fungi and Bacteria, (35).
Morton, D. J., Crossan, D. F., and Manning, W. J. 1967. Reduction of cucurbit scab by a one-year rotation with corn. Plant Dis. Rep. 51:495-497.
Vakalounakis, D. J. 1993. Inheritance and genetic linkage of Fusarium wilt (Fusarium oxysporum f. sp. cucumerinum race 1) and scab (Cladosporium cucumerinum) resistance genes in cucumber (Cucumis sativus). Ann. Appl. Biol. 123:359-365.
Keinath, A. P., Wintermantel, W. M., & Zitter, T. A. (2017). Compendium of cucurbit diseases and Pests (No. Ed. 2, pp. 228-pp).
Shi, Y., Meng, S., Xie, X., Chai, A., & Li, B. (2016). Dry heat treatment reduces the occurrence of Cladosporium cucumerinum, Ascochyta citrullina, and Colletotrichum orbiculare on the surface and interior of cucumber seeds. Horticultural Plant Journal, 2(1), 35-40.
Park, S., Hong, S., Shim, C., Kim, M., Park, J., Han, E., & Kim, A.Y. (2017). Screening for Effective Organic Farming Materials for the Control of Cucumber Scab Caused by Cladosporium cucumerinum. Radiation Protection Dosimetry, 23, 159-167.
Cucurbita spp.
squash, pumpkin, gourd
Uncertain
CLADCU-3, CLADCU-4, CABI CPC, CLADCU-7, CLADCU-10
Squash and pumpkin seeds have been cited in older literature as possible pathways for Cladosporium cucumerinum, primarily by inference rather than direct evidence. Natural seed transmission has not been documented, and no recent studies confirm seed as a pathway; therefore, Cucurbita seeds remain an uncertain pathway for this pathogen.
Yes
Freezing blotter
Used to identify Cladosporium spp. on seed, but did not identify the Cladosporium to species. This method has not been validated or standardized.
CLADCU-4
Chemical, cultural
Use clean seed, rotate crops, and remove infected debris to reduce inoculum; seed testing or treatment may help limit potential seed-associated risk.
CABI CPC, CLADCU-10
2025-12-22 18:46:22
Zitter, T.A. Scab 2016. The American Phytopathologogical Society APSnetfeatures. (http://www.apsnet.org/publications/apsnetfeatures/Pages/Scab.aspx) St. Paul, MN
Cassaroli, D., Garcia, D.C., Muniz, M.F.B & Menezes, N.L. 2006. Qualidade sanitária e siológica de sementes de abóbora variedade Menina Brasileira. Fitopatologia Brasileira 31:158-163
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Ellis, M.B. and Holliday, P., 1972. Cladosporium cucumerinum.[Descriptions of Fungi and Bacteria]. IMI Descriptions of Fungi and Bacteria, (35).
Keinath, A. P., Wintermantel, W. M., & Zitter, T. A. (2017). Compendium of cucurbit diseases and Pests (No. Ed. 2, pp. 228-pp).
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