Citrullus lanatus
watermelon
27 Related Pests
Cucumber green mottle mosaic virus
virus
Bottlegourd Indian mosaic virus, Cucumber green mottle mosaic virus, Cucumber mottle virus, Cucumber virus 2, 3 or 4, Cucumis virus 2, Tobacco mosaic virus watermelon strain
Asia: China, Georgia, India, Iran, Israel, Japan, Jordan, Lebanon, Myanmar, Pakistan, Sudan, South Korea, Sri Lanka, Syria, Taiwan, Thailand, Turkey. Europe: Austria, Bulgaria, Denmark, Finland, France, Germany, Greece, Hungary, Latvia, Lithuania, Moldova, Netherlands, North Macedonia, Norway, Poland, Romania, Russia, Spain, Sweden, UK. America: Canada. Australia.
CA
Many countries
2023-12-19
Primarily found externally on the seed coat. Mechanical transmission primary the means of spread. Natural infections of Cucurbita pepo (squash and pumpkin) are not known to occur.
watermelon, gerkin, melon, cucumber, bottlegourd, rootstock, Prunus and Gladiolus spp. in experimentation
Yes
CGMMV-2, CABICPC, ISFRPLD
Seed is known to be a pathway. Watermelon seeds are commonly tested for Cucumber green mottle virus.
NSHS
CGMMV-2, CABICPC, ISFRPLD
ELISA
CGMMV-3, NSHSUSDA
This method is a standard method of the NSHS.
Thermotheropy-3 days at 72 C; Chemotheropy-10% trisodium phosphate
CGMMV-2, CABICPC
Test seed after treatment to determine effectiveness.
Hollings M, Komuro, Y, Tochihara, H, 1975. Cucumber green mottle mosaic virus Datasheet 154. Descriptions of Plant Viruses. http://dpvweb.net/dpv/
Detection of Squash Mosaic Virus, Cucumber Green Mottle Mosaic Virus and Melon Necrotic Spot Virus in cucurbit seed. International Seed Testing Association. International Rules for Seed Testing 7-026: Seed Health Testing Methods. 2024 https://www.seedtest.org/en/international-rules-for-seed-testing/seed-health-methods-product-1014.html
Acidovorax avenae subsp. citrulli
bacterium
Acidovorax citrulli, Pseudomonas avenae subsp. citrulli, Pseudomonas pseudoalcaligenes subsp. citrulli
Worldwide
Midwest and Southeast States, CA, OR
2023-04-10
Wild cucurbit species and cucurbit volunteers are known hosts. Occassional reports, but unsubstantiated infections in pepper and tomato
watermelon, melon, squash, pumpkin, cucumber, root stock.
Yes
PSDMAC-1, PSDMAC-6
Seed as a pathway well documented and accepted for this pathogen
Seedling Grow out and PCR tests are NSHS standard tests (PSDMAC-4)
PSDMAC-1, PSDMAC-6
Seedling Grow out, PCR tests, Immunomagnetic separation-PCR wash
PSDMAC-1, PSDMAC-4
No
PSDMAC-6
Clean seed programs including exclusion, cultural practices, sanitation and copper sprays when needed, decreased seed infestations but did not eradicate.
Acidovorax avenae subsp. citrulli In: Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
International Seed Federation Pest List Database 2016. pestlist.worldseed.org Nyon Switzerland
Acidovorax avenae subsp. citrulli Seed Health Testing Method Mz 10.1 National Seed Health System www.seedhealth.org
Xanthomonas cucurbitae
bacterium
Xanthomonas campestris pv. cucurbitae, Bacterium cucurbitae, Phytomonas cucurbitae, Pseudomonas cucurbitae
China, India, Nepal, Japan, Brunei, France, Italy, Egypt, Seychelles, Argentina, Brazil, Uruguay, Trinidad and Tobago, Australia, New Zealand, Canada, Russia
Widespread
Mexico, Korea, Nepal
2023-09-07
When symptoms are present, confirm the causal agent with laboratory diagnoses. Symptoms of this disease may be suppressed, indistinguishable from other diseases or inconspicuous under unfavorable climatic conditions or plant physiological stress, requiring thorough laboratory analysis. Prolonged periods of latency resulting in asymptotic plants has not been documented for this pathogen, though the period from infection to symptom expression may vary with climatic conditions, plant genetics, physiological stress and plant pathogen strain. Literature showing that random sampling of apparently healthy plants to detect latent populations of this pathogen has not been found.
Cucurbits
No
XANTCU-2, XANTCU-7, ISFRPLD
The pathogen has been reported on watermelon, but seed as a pathway has not been proven. Movement of the pathogen to seedlings was not shown to occur in controlled experiments. Seed as a pathway for transmission of Xanthomonas cucurbitae appears to be minor or insignificant. Currently seed as a pathway has only been shown on species of Cucurbita (pumpkin).
XANTCU-2, XANTCU-7, ISFRPLD
CABICPC
Use good seed growing practices. Grow in disease free areas and in arid climates. No overhead irrigation. Copper sprays when needed
Babadoost, 2016. Personnel communication University of Illinois:
Babadoost, 2012. Bacterial spot of Cucurbits. Report on Plant disease. No. 949, December 2012. University of Illinois Extension. (http://extension.cropsci.illinois.edu/fruitveg/pdfs/949_bacterial_spot.pd)
Pseudomonas syringae pv. lachrymans
bacterium
Bacillus lachrymans, Bacterium burgeri, Bacterium lachrymans, Chlorobacter lachrymans, Phytomonas lachrymans, Pseudomonas burgeri, Pseudomonas lachrymans, Pseudomonas lachrymans f. cucumis
Africa: Algeria, Egypt, Gabon, Kenya, South Africa, Zimbabwe; Asia: China, India, Israel, Japan, Jordan, Kazakhstan, Laos, North Korea, Philippines, South Korea, Tajikistan, Thailand, Turkey, Uzbekistan; Europe: Australia, Belarus, Bulgaria, Czechia, Denmark, France, Germany, Greece, Hungary, Italy, Moldova, Netherlands, Romania, Russia, Slovakia, Switzerland, Ukraine, UK; North America: Canada, Guadeloupe, Martinique, Nicaragua, Puerto Rico, Trinidad and Tobago, USA: Oceania: Australia, New Zealand; South America: Argentina, Brazil, Colombia, Venezuela.
Widespread
MX
2024-10-16
This pathogen occurs in MX
Main: Cucurbitaceae family
uncertain
PSDMLA-2, CABI CPC, ISF RPLD, PSDMLA-5, PSDMLA-7, PSDMLA-10
Watermelon is a host of this pathogen. No evidence of seed as a pathway was found. Often inferred as seed-borne because it is seed-borne in cucumber.
PSDMLA-2, CABI CPC, ISF RPLD, PSDMLA-5, PSDMLA-7, PSDMLA-10
Ohuchi A, Hayashi N, Sakai Y, Ezuka A, 1980. Bacteriological properties and pathogenicity of Pseudomonas lachrymans, the causal agent of angular leaf spot of cucumber, from Japan. Bulletin of the National Institute of Agricultural Sciences, C, No.34:1-13
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
International Seed Federation Regulated Pest List Database. pestlist.worldseed.org Nyon Switzerland
Shila, S. J., Islam, M. R., Ahmed, N. N., Dastogeer, K. M. G., & Meah, M. B. (2013). Detection of Pseudomonas syringae pv. lachrymans associated with the seeds of cucurbits. Universal Journal of Agricultural Research, 1(1), 1-8.
Kritzman G, Zutra D, 1983. Systemic movement of Pseudomonas syringae pv. lachrymans in the stem, leaves, fruits, and seeds of cucumber. Canadian Journal of Plant Pathology, 5(4):273-278
Leben C, 1981. Survival of Pseudomonas syringae pv. lachrymans with cucumber seed. Canadian Journal of Plant Pathology, 3(4):247-249
Ralstonia solanacearum
bacterium
Bacillus musae, Bacillus musarum, Bacillus nicotianae, Bacillus sesami, Bacillus solanacearum, Bacterium solanacearum, Bacterium solanacearum var. asiatica, Bacterium solanacearum var. asiaticum, Burkholderia solanacearum, Chromobacterium nicotianae, Erwinia nicotianae,
Erwinia solanacearum, Phytobacterium solanacearum, Phytomonas ricini, Phytomonas solanacearum, Phytomonas solanacearum var. asiatica, Pseudomonas batatae, Pseudomonas ricini,
Pseudomonas solanacearum, Pseudomonas solanacearum var. asiatica, Pseudomonas tectonae,
Xanthomonas solanacearum, Xanthomonas solanacearum var. asiatica
Worldwide
AL, AR, CT, DE, FL, GA, HI, IL, IN, LA, MI, NH, NJ, NY, NC, PA, SC, SD, VA, WI
China
2025-08-13
Ralstonia solanacearum spreads mainly through infected vegetative planting material, contaminated soil or water, root contact, mechanical injury, and sometimes insect vectors, with wild hosts serving as reservoirs that can contaminate irrigation sources. True seed infection is rare and confirmed in peanut, while seed contamination in other crops such as tomato, pepper, eggplant, and soybean has been reported but not substantiated, making seed a minor pathway compared with other transmission routes. Pest is on USDA Plant Protection and Quarantine Select Agents and Toxins list.
Over 250 species, particularly tropical and subtropical crops, are susceptible to races of the R. solanacearum species complex, with tomato, tobacco, aubergine, potato, banana, plantain, and Heliconia being the most significant worldwide, while other hosts include Anthurium spp., groundnut, Capsicum annuum, cotton, rubber, sweet potato, cassava, castor bean, and ginger.
No
CABI CPC
Watermelon is not considered an important host of the pathogen. Seed is not known to be a pathway.
CABI CPC
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Colletotrichum orbiculare
fungus
Colletotrichum lagenarium, Glomerella lagenarium
Worldwide, wherever cucurbits are grown.
Widespread, wherever cucurbits are grown
Mexico, Chile
2022-11-11
Cucurbitaceae family
No
COLLLA-1, COLLLA-2, COLLLA-3, COLLLA-5, COLLLA-6
Pathway not proven. Though seed is often listed as a pathway and research using artificially inoculated seed was found, there has been no research or showing seed is a pathway for this pathogen on this host in nature.
COLLLA-1, COLLLA-2, COLLLA-3, COLLLA-5, COLLLA-6
Blotter incubation
COLLLA-6
Though not proven to be seed borne, Blotter assays using methods described for Didymella bryoniae (gummy stem blight) are commonly used in the seed industry.
COLLLA-3
Although not proven to be seedborne in cucurbits, a seed treatment is recommended
Colletotrichum orbiculare In: Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc."
Koike ST, Tidwell TE, Fogle DG, Patterson CL, 1991. Anthracnose of greenhouse-grown watermelon transplants caused by Colletotrichum orbiculare in California. Plant Disease, 75:644
Madaan RL, Grover RK, 1979. Chemical control of Colletotrichum lagenarium causing anthracnose and scab of bottle gourd. Indian Phytopathology, 32:210-215
Vakalounakis, DJ. 1996. In, Compendium of Cucurbit Diseases. Eds. Zitter, TA, Hopkins DL and Thomas CE. APS Press, Minniapolis, MN
International Seed Federation Regulated Pest List Database. www.pestlist.worldseed.org. Nyon Switzerland
Alternaria cucumerina
fungus
Alternaria brassicae var. nigrescens, Macrosporium cucumerinum, Alternaria loofahae
Worldwide
Widespread
Mexico
2022-09-21
Distribution information from USDA GRIN
Cucurbitaceae family
No
ALTECU-3, ALTECU-4
Pathway not proven. According to Thomas,1996, artificially infested seed has resulted in seedling infection, but infection was low. Spread from naturally infested seed has not been demonstrated.
ALTECU-3, ALTECU-4
Seed treatments are often inferred as effective, but no data exists and seed has not been proven to be a pathway.
ALTECU-4
A quality systems approach in production of the seeds with crop inspections, careful selection of healthy fruits and seed conditioning and cleaning should be used to ensure seed quality and reduce unwanted seed contaminants.
Cladosporium cucumerinum
fungus
Cladosporium cucumeris, Cladosporium scabies, Macrosporium cucumerinum, Macrosporium melophthorum, Scolicotrichum melophthorum
Worldwide
FL. ME, MI, NY, NC, OK, OR, TX, WA
China
2022-11-11
Widespread in many cool, temperate regions of the world. This pathogen is known to occur in China.
cucumber, pumpkin, gourd,melon, watermelon
No
CLADCU-1, CLADCU-3
Pathway not proven. Though seed is often listed as a pathway, there has been no research or literature found showing seed is a pathway for this pathogen on this host. Seed pathway may be inferred because the pest can be associated with seed in Cucurbita spp. and C. sativus.
CLADCU-1, CLADCU-3
No test specific for C. lanatus was found. Freezing blotter has been used for Cucurbita spp.
Seed surface-disinfestation with 0.5% sodium hypochlorite for 10 min to decrease all fungal contamination
CLADCU-1
Verticillium dahliae
fungus
Verticillium albo-atrum f. angustum.
Verticillium albo-atrum var. chlamydosporale
Verticillium albo-atrum var. dahliae
Verticillium albo-atrum var. medium.
Verticillium dahliae f. angustum
Verticillium dahliae f. cerebriforme
Verticillium dahliae f. chlamydosporale
Verticillium dahliae f. medium
Verticillium dahliae f. zonatum
Verticillium ovatum
Verticillium trachiephilum
Worldwide
Widespread
China
2022-11-11
Prevalent in China
Verticillium dahliae has a broad host range, infecting both woody and herbaceous plants, including ornamentals, native species, and weeds. Economically important hosts include artichoke, eggplant, bell pepper, cotton, hop, lettuce, mints, oilseed rape, olive, potato, strawberry, and tomato.
No
VERTDA-12, VERTDA-16, VERTDA-26, VERTDA-3, VERTDA-4, VERTDA-5, CABI CPC, EPPO
Verticillium dahliae has been reported on watermelon. No references found indicating seed as a pathway for Verticillium dahliae in watermelon.
VERTDA-12, VERTDA-16, VERTDA-26, VERTDA-3, VERTDA-4, VERTDA-5, CABI CPC, EPPO
Bruton, B.D., Fish, W.W., Subbarao, K.V., and Isakeit, T. 2007. First Report of Verticillium Wilt of Watermelon in the Texas High Plains. Pl. Dis. 91: 1053
Richardson, MJ. 1990. An Annotated List of Seedborne Diseases. International Seed Testing Association. Zurich, Switzerland.
International Seed Federation Regulated Pest List Database. www.pestlist.worldseed.org. Nyon, Switzerland
Vallad, G.E., Bhat, R.G., Koike, S.T., Ryder, E.J. and Subbarao, K.V. (2005). Weedborne reservoirs and seedborne transmission of Verticillium dahliae in lettuce. Plant Disease, 89, 317-324.
Zitter, T.A., Hopkins, D.L. and Thomas, C.E. (Eds) (1996). Compendium of Cucurbit Diseases. American Phytopathological Society (APS Press): St. Paul, Minnesota (USA). 120pp.
du Toit, L.J. and Hernandez-Perez, P. (2005). Efficacy of hot water and chlorine for eradication of Cladosporium variabile, Stemphylium botryosum, and Verticillium dahliae from spinach seed. Plant Disease, 89 (12), 1305-1312.
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
OEPP/EPPO Global Database - European and Mediterranean Plant Protection Organization
Tobacco ringspot virus
virus
Anemone necrosis virus, Annulus tabaci, Blueberry necrotic ringspot virus, Nicotiana virus 12, Soybean bud blight virus, Tobacco Brazilian streak virus, Tobacco ringspot nepovirus, Tobacco ringspot virus No. 1
Worldwide
Widespread
Korea, China
2025-09-15
Tobacco ringspot virus is a Nepovirus with a broad host range that causes ring spots, mottling, stunting, and yield loss. It is transmitted primarily by dagger nematodes (Xiphinema spp.) in soil, but can also spread through infected seed in certain crops (mainly soybeans), mechanical contact with sap or contaminated tools, and, in some cases, via infected pollen.
Extensive host range includes many weed, fruit and ornamental plant species. Main: peppers, watermelon, melon, cucumber, soybean, tomato.
No
TRSV00-1, TRSV00-2, CABI CPC, DPV WEB, TRSV00-12
No references found indicating watermelon seed is a pathway.
TRSV00-1, TRSV00-2, CABI CPC, DPV WEB, TRSV00-12
Tobacco Ringspot Virus. In: Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Richrdson, MJ 1990. An Annotated List of Seed-Borne Diseases. Foruth Ed. The International Seed Testing Association, Zurich, Switzerland
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Description of Plant Viruses ; http://dpvweb.net/dpv/
Abdalla, O.A., Bruton, B.D., Fish, W.W., Ali, A., 2012 . First confirmed report of Tobacco ringspot virus in cucurbits crops in Oklahoma.Plant Disease, 96 ( 11 ): 1705
Melon necrotic spot virus
virus
Worldwide
CA
Mexico
2023-08-21
Only systemic in Cucumis melo (melon). Local lesions produced in Cucumis sativus (cucumber), Citrullus lanatus (watermelon), Cucurbita moschata (pumpkin), Lagenaria siceraria (bottle gourd), Vigna unguiculata (cowpea), Vigna unguiculata ssp. Sesquipedalis (yardlong bean).
No
MNSV00-5, DVPWEB
Pathway not proven. Only a local lesion host and not commonly systemic in this host. Seed transmission inferred because of seed transmission in melon, but no references found indicating watermelon seed is a pathway.
MNSV00-5, DVPWEB
Squash mosaic virus
virus
Cucurbit ring mosaic virus, Muskmelon mosaic comovirus, Muskmelon necrotic mosaic virus, pumpkin mosaic virus, squash mosaic comovirus
Africa: Egypt, Morocco, Tunisia; Asia: Bangladesh, China, India, Iran, Israel, Japan, Jordan, Kazakhstan, Lebanon, Philippines, Syria, Turkey, Yemen; Europe: Bulgaria, Cyprus, Czechia, Greece, Italy, Netherlands; North America: Canada, Honduras, Jamaica, Mexico, Montserrat, Puerto Rico, Trinidad and Tobago, USA; Oceania: Australia, New Zealand, Samoa; South America: Argentina, Brazil, Chile, Venezuela.
AL, AZ, AR, CA, FL, IL, MA, MI, NY, OK, TX, WI
Korea, Mexico
2024-12-22
Squash mosaic virus is transmitted by numerous insect species, mostly beetles. Seed is also a pathway for certain species.
Main: Cucurbitaceae family. Also infects Amaranthaceae, Apiaceae, Chenopodiaceae, Fabaceae, and Hydrophyllaceae
uncertain
SQMV00-10, SQMV00-9, CABI CPC, DPV WEB
No field observations of squash mosaic virus in watermelon. Watermelon infection by squash mosaic virus only an experimental curiosity and not found in nature.
ELISA, positive confirmation by Grow out is the standard method of the NSHS.
SQMV00-10, SQMV00-9, CABI CPC, DPV WEB
ELISA and grow out
NSHS USDA
This method is the standard method of the NSHS.
Chemical, cultural
CABI CPC
Insecticides to control beetle populations can reduce spread. Remove infected seedlings. Use disease-free seed.
International Seed Federation Pest List Database. http://www.worldseed.org Nyon Switzerland
Nelson, MR, and Kunhtsen HK, 1973, Squash mosaic virus variability: epidemiological consequences of differences in seed transmission frequency between strains. Phytopathology 63:918-920
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Description of Plant Viruses ; http://dpvweb.net/dpv/
United Stated Department of Agriculture, Animal and Plant Health Protection Service National Seed Health System (USDA-APHIS NSHS) www.seedhealth.org
Tobacco mosaic virus
virus
TMV U1, type, Vulgare or Common strain
tobacco mosaic tobamovirus,
VMT (Virus mosaique de tabac)
Worldwide
Widespread
Mexico
2023-08-21
Broad host range. Cultivated species listed below.
No
Occasionally listed as a host, no evidence that seed is a pathway.
Tomato spotted wilt virus
virus
Tomato spotted wilt tospovirus, Tomato spotted wilt virus group
Worldwide
Widespread
2023-08-21
Seed is not a pathway for Tospoviruses, including Tomato spotted wilt virus
Wide host range. Over 800 plant species are known hosts. Primarily ornamentals,flowers. No evidence that small grains or corn are hosts.
No
TSWV00-1, TSWV00-2
Seed is not a pathway for Tospoviruses, including Tomato spotted wilt virus
TSWV00-1, TSWV00-2
Phomopsis sclerotioides
fungus
Diaporthe sclerotioides
Asia: India, Malaysia; Europe: Austria, Denmark, France, Germany, Netherlands, Norway, Sweden, Switzerland, UK; North America: Canda, USA
WA
Korea
2025-09-05
Phomopsis sclerotioides is a strong saprophytic fungus that survives in soil, forming sclerotia that can persist for years under adverse conditions. It rapidly colonizes clean or sterilized soil, requiring thorough disinfection to manage. The fungus is dispersed through water, air, and soil particles.
Main: cucumber, cucurbits
No
PHOPSC-3, PHOPSC-5
No evidence that seed is a pathway. Primarily found in greenhouse soils.
PHOPSC-3, PHOPSC-5
Bruton BD and Biles CL. 2017. Phomosis Black Root Rot of Cucumber. In, Compendium of Cucurbit Diseases and Pests, Second Edition. Keinath AP, Wintermantel WM and Zitter TA, eds. The American Phytopathological Society, St. Paul, MN.
Richardson, M.J. 1990. An Annotated List of Seed-Borne Diseases. Fourth Edition. International Seed Testing Association, Zurich, Switzerland
Cucumber leaf spot virus
virus
Cucumber fruit streak virus
Asia: Iran; Europe: Bulgaria, Poland
Not known to occur
China, Nepal
2025-09-12
Cucumber leaf spot virus is transmitted in the field by the soil-inhabiting fungus Olpidium bornovanus, which carries virus particles to plant roots. Mechanical transmission is also possible under experimental conditions. Reports of seed transmission are unsubstantiated, and the main natural pathway of spread is through the fungal vector.
Main: cucumber
Not a host
CLSV00-2, CABI CPC, DPV WEB
Watermelon has only been shown to be a host in laboratory studies and only produces local lesions. No references found indicating that watermelon is a natural host for this virus.
CLSV00-2, CABI CPC, DPV WEB
Pythium vexans
fungus
Pythium complectens, Phytopythium vexans, Pythium allantocladon, Pythium ascophallon, Pythium piperinum, Ovatisporangium vexans, Pythium euthyphyphon, Pythium polycladon
Africa, Asia, Europe, Guatemala, Caribbean, Fiji, Papua New Guinea, Samoa, Solomon Islands, Argentina, Brazil, Venezuela, Chile, South Korea, New Zealand, Canada
HI, OK, CA, NC, MD, VA, DE, PA, NJ, WA, TN, LA, WI, IA
Korea
2023-08-21
Primarily affecting seedlings and roots and is transmitted mainly through infested soil. Seed is not known to be a pathway for any host. Zoospores of this fungus can swim in open water for a short distance. This pathogen has been reported in S. Korea. Korea lists this pathogen as Phytopythium vexans
Wide host range
No
PYTHVE-1, PYTHVE-3
Seed is not known to be a pathway for any host.
PYTHVE-1, PYTHVE-3
Tomato leaf curl New Delhi virus
virus
Tomato leaf curl New Delhi begomovirus, ToLCNDV
Africa: Algeria, Morocco, Seychelles, Tunisia; Asia: Bangladesh, China, India, Indonesia, Iran, Nepal, Pakistan, Philippines, Sri Lanka, Taiwan, Thailand, Turkey; Europe: France, Greece, Italy, Portugal,Slovakia, Spain,.
Not known to occur
Korea
2024-11-09
Tomato leaf curl New Delhi virus is transmitted by the whitefly. Seed transmission of ToLCNDV has not been reported.
ToLCNDV affects a wide spectrum of plant species. Main are the Cucurbitaceae and Solanaceae families.
No
CABICPC
Seed is not known to be a pathway.
CABICPC
Pratylenchus fallax
nematode
Turkey, Canada
WI, ND, OR
Korea
2025-08-13
Pratylenchus fallax is a root-lesion nematode that damages plant roots and is primarily spread through infested soil, water, and plant material, with agricultural activities such as tillage and the use of machinery aiding its dispersal. Seed is not known to be a pathway.
beet, wheat, barley, soybean, rapeseed, ryegrass, corn, sugarbeet, bluegrass,
Not a host
CABI CPC, PRATFA-1, PRATFA-2, PRATFA-3, PRATFA-4, PRATFA-5, PRATFA-6
Watermelon is not a host.
CABI CPC, PRATFA-1, PRATFA-2, PRATFA-3, PRATFA-4, PRATFA-5, PRATFA-6
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Rivedal, H. M., Zasada, I. A., Temple, T. N., Peetz, A. B., Núñez-Rodríguez, L. A., Starchvick, R. J., & Braithwaite, E. T. (2024). Plant-parasitic Nematodes Associated with Grasses Grown for Seed in the Willamette Valley of Oregon. Journal of Nematology, 56(1), 20240020.
Corbett, D.C.M. 1972. The effect of Pratylenchus fallax on wheat barley and sugar beet roots. Nematologica 18:303-308.
Yu, Q. 2008. Species of Pratylenchus (Nematoda: Pratylenchidae) in Canada: description, distribution, and identification. Canadian J. Plant Pathology 30:477-485.
Zasada I. A., Dandurand L.M., Gleason C., Hagerty C. H., Ingham R. E. Subbotin S. A., Chitambar J. J. Plant parasitic nematodes in sustainable agriculture of North America. Cham, Switzerland: Springer; 2018. Plant parasitic nematodes of the Pacific Northwest: Idaho, Oregon and Washington; pp. 211–239
Kantor M., Handoo Z., Kantor C., Carta L.. Top ten most important U.S.-regulated and emerging plant-parasitic nematodes. Horticulturae. 2022;8:208.
Nemaplex.UCDavis.edu; Revision Date: 16-December-2024; Accessed 13-August-2025
Xiphinema diversicaudatum
nematode
Dorylaimus diversicaudatus, Dorylaimus elongatus apud, Longidorus diversicaudatus, Xiphinema diversicaudatum, Xiphinema amarantum, Xiphinema basiri apud, Xiphinema israeliae apud, Xiphinema paraelongatum, Xiphinema sahelense apud, Xiphinema seredouense
Africa: Morocco, South Africa; Asia: India, Turkey; Europe: Austria, Belgium, Croatia, Czechia, Denmark, France, Germany, Ireland, Italy, Moldova, Netherlands, Norway, Poland, Portugal, Russia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Urkaine, UK; North America: USA. Oceania: New Zealand.
CA
Korea
2024-09-09
Found primarily in pasture and woodland areas. May spread nepoviruses. Seed is not known to be a pathway for dagger nematodes.
Wide host range
No
XIPHDI-1, CABICPC
Seed is not known to be a pathway.
XIPHDI-1, CABICPC
Pratylenchus brachyurus
nematode
Anguillulina brachyura, Pratylenchus leiocephalus, Pratylenchus pratensis, Pratylenchus steineri, Tylenchus brachyurus
Worldwide, primarily in tropical and subtropical regions.
AL, AR, CA, FL, GA, HI, KY, LA, MD, MS, NC, OK, SC, TN, TX, VA
Korea
2025-08-13
Pratylenchus brachyurus is a root-lesion nematode that reproduces mainly by mitotic parthenogenesis. It spends its entire life cycle inside plant roots or in surrounding soil, feeding and moving within root tissues. Eggs overwinter in roots or soil, hatching in spring to resume infection. Seed is not known to be a pathway.
Wide host range. Main hosts of economic importance: pineapple, potatoes, peanuts, cotton, tobacco, peaches, cereals, coffee, soybean.
No
PRATBR-4, PRATBR-5, PRATBR-6, PRATBR-7, PRATBR-8
Seed is not known to be a pathway for this nematode in any host.
PRATBR-4, PRATBR-5, PRATBR-6, PRATBR-7, PRATBR-8
Nemaplex.UCDavis.edu; Revision Date: 16-December-2024; Accessed 13-August-2025
Nomura, R. B. G., Lopes-Caitar, V. S., Hishinuma-Silva, S. M., Machado, A. C. Z., Meyer, M. C., & Marcelino-Guimarães, F. C. (2024). Pratylenchus brachyurus: status and perspectives in Brazilian agriculture. Tropical Plant Pathology, 49(5), 573-589.
Agrios, G. N. 2005. Plant Pathology, 5th Edition. Elsevier Academic Press. 922 pp
Chitambar, J. J., Westerdahl, B. B., and Subbotin, S. A. 2018. Plant Parasitic Nematodes in California Agriculture. In Subbotin, S., Chitambar J., (eds) Plant Parasitic Nematodes in Sustainable Agriculture of North America. Sustainability in Plant and Crop Protection. Springer, Cham.
Scheck, H.J. 2023. California Pest Rating Proposal for Pratylenchus brachyurus (Godfrey, 1929) Filipjev & Schuurmans-Stekhoven, 1941 smooth-headed lesion nematode. California Department of Food and Agriculture, Sacramento, California, USA,
Golovinomyces orontii
fungus
Erysiphe orontii, Erysiphe polyphaga, Erysiphe tabaci, Oidium begoniae, Oidium violae
Worldwide
AZ, CA, GA, ID, MA, MO, SC, TX, WA
Korea
2024-09-07
Korea lists this pathogen as Erysiphe orontii. Seed is not a pathway. Wind-borne conidia most common means of dispersal.
Main: sugarbeet, pepper, watermelon, melon, cucumber, pumpkin, pea, tomato, eggplant, potato.
No
CABICPC
No references found indicating seed is a pathway.
CABICPC
CABICPC
Seed treatment to control powdery mildew on seedlings from wind blown spores during the first 1.5 weeks of growth.
Alternaria alternata
fungus
Alternaria alternata f.sp. fragariae
Alternaria alternata f.sp. lycopersici
Alternaria fasciculata
Alternaria tenuis
Worldwide
AL, CA, FL, GA, IL, IA, LA, MI, MS, NY, OR, PA, SD, TN, TX
Korea
2025-09-08
Alternaria alternata is a widespread fungus that can persist in soil and crop debris for many years, enabling it to infect plants across successive growing seasons. Its spores are dispersed by air, wind, water splash, irrigation, and contact with contaminated plant material. Numerous studies have demonstrated its transmission under experimental conditions, and it has been shown to be seed-transmitted in a few crops within the Malvaceae family.
Main: allium, pepper; Other: watermelon, sunflower, sorghum, spinach, marigold, many fruits and trees
No
ALTEAL-4
No references found indicating that watermelon seed is a pathway.
ALTEAL-4
Richardson MJ, 1990. An Annotated List of Seed-borne Disease. International Seed Testing Association, Zurich, Switzerland
Didymella bryoniae
fungus
Stagonosporopsis cucurbitacearum, Ascochyta citrullinaAscochyta cucumis, Ascochyta melonis, Cercospora citrullinaCercospora cucurbitae, Didymella melonis, Didymosphaeria bryoniae, Didymosphaeria effusa, Didymosphaeria melonisMycosphaerella citrullina, Mycosphaerella melonis,Phoma cucurbitacearum, Phyllosticta citrullina, Sphaerella bryoniae, Sphaeria bryoniae
Worldwide
FL, GA, NY, NC, SC
Nepal
2023-09-08
Cucumber, watermelon, melon, squash and pumpkin
Yes
CABICPC, ISFRPLD, DIDYBR-3, ARSGRIN, ANNOLIST, DIDYBR-4
Seed is a known pathway.
CABICPC, ISFRPLD, DIDYBR-3, ARSGRIN, ANNOLIST, DIDYBR-4
Blotter, PCR
NSHSUSDA
Both blotter and PCR are the temporary standard of the NSHS.
ChemicalÂ
CABICPC, DIDYBR-1, DIDYBR-2
Seed treatment with fungicides has shown to be effective. D. bryoniae can survive on seeds, weeds, and plant debris from previously infected cucurbit crops. It is recommended to use only disease-free seed, and evaluate seed production through field inspections.
Keinath, A. P. (2011). From native plants in central europe to cultivated crops worldwide: The emergence of didymella bryoniae as a cucurbit pathogen. HortScience, 46(4), 532–535. https://doi.org/10.21273/hortsci.46.4.532
El-Wakil, A.-F., Khalil, A., & El -Abbasi, I. (2017). Factors promoting pycnidia production of didymella bryoniae, the causal of gummy stem blight in cucurbits. Egyptian Journal of Phytopathology, 45(1), 173–187. Retrieved September, 2023, from https://doi.org/10.21608/ejp.2017.89736
Miller SA, Rowe CR, Riedel MR, 2001. The Ohio State University Gummy Stem Blight and Black Rot of Cucurbits HYG-3126-96.
Hopkins, D. L., Thompson, C. M., Hilgren, J., & Lovic, B. (2003). Wet seed treatment with peroxyacetic acid for the control of bacterial fruit blotch and other seedborne diseases of watermelon. Plant Disease, 87(12), 1495–1499. Retrieved September, 2023, from https://doi.org/10.1094/pdis.2003.87.12.1495
Erwinia tracheiphila
bacterium
Bacillus tracheiphilus, Bacillus tracheiphilus f.sp. cucumis,Bacterium tracheiphilum, Erwinia amylovora var. tracheiphila
Democratic Republic of the Congo, South Africa, Asia, Lithuania, Canada,
AL, NM
Nepal
2023-09-11
There are no records of E. tracheiphila being seed- or pollen-borne, nor is it known to be spread in soil, water, or by wind. The bacteria is dependent on the striped cucumber beetle Acalymma vittata and the spotted cucumber beetle Diabrotica undecimpunctata howardi for dispersal. (CABI)
cucurbit spp.
No
CABICPC, ERWITR-2, ERWITR-3
Seed is not known to be a pathway.
CABICPC, ERWITR-2, ERWITR-3
CABICPC, ERWITR-4
Management of the disease relies on controlling two vector species. Insecticide applications have proven to be effective in reducing cucumber beetles as well as using a Permiter Trap Crop (PTC) or border crops to intercept pests. Aggressively controlling beetles in early-planted crops can help late-plantings.
Sanogo, S., Etarock, B. F., & Clary, M. (2011). First report of bacterial wilt caused by erwinia tracheiphila on pumpkin and watermelon in new mexico. Plant Disease, 95(12), 1583–1583. Retrieved September, 2023, from https://doi.org/10.1094/pdis-06-11-0507
Olawole, O. I., Gleason, M. L., & Beattie, G. A. (2022). Expression and functional analysis of the type iii secretion system effector repertoire of the xylem pathogen erwinia tracheiphila on cucurbits. Molecular Plant-Microbe Interactions®, 35(9), 768–778. Retrieved September, 2023, from https://doi.org/10.1094/mpmi-01-22-0002-r
Rojas, E., Batzer, J. C., Beattie, G. A., Fleischer, S. J., Shapiro, L. R., Williams, M. A., Bessin, R., Bruton, B. D., Boucher, T., Jesse, L. H., & Gleason, M. L. (2015). Bacterial wilt of cucurbits: Resurrecting a classic pathosystem. Plant Disease, 99(5), 564–574. Retrieved September, 2023, from https://doi.org/10.1094/pdis-10-14-1068-fe
Melon rugose mosaic virus
virus
Tymovirus melonis
Asia: Sudan, Yemen
n/a
2024-02-19
Only one reference was found, which advises seed transmission occurred in experiments through mechanical inoculation. No other references note seed is a pathway for MRMV00.
melon
No
MRMV00-1
Watermelon can be a host of MRV00, however, no references found indicating seed as a pathway.
MRMV00-1
Mahgoub, H. A., Wipf-Scheibel, C., Delécolle, B., Pitrat, M., Dafalla, G., & Lecoq, H. (1997). Melon rugose mosaic virus: Characterization of an isolate from sudan and seed transmission in melon. Plant Disease, 81(6), 656–660. https://doi.org/10.1094/pdis.1997.81.6.656
Monosporascus cannonballus
fungus
-
Africa: Egypt, Tunisia; Asia: China, India, Iran, Iraq, Israel, Japan, Oman, Saudi Arabia, South Korea, Taiwan; Euope: Greece, Italy, Spain; North America: Guatemala, Honduras, Mexico, USA; South America: Brazil.
AZ, CA, TX
China
2024-10-23
Monosporascus cannonballus is soilborne in hot, arid climates.
Restricted to melon, watermelon, bottle gourd
No
CABICPC, ISFRPLD
seed is not a known pathway.
CABICPC, ISFRPLD
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