Lactuca sativa
lettuce
27 Related Pests
Tobacco streak virus
virus
Annulus orae, Asparagus stunt virus, Black raspberry latent ilarvirus, Datura quercina virus, New logan virus, Micotiana virus 8, Nicotiana virus vulaerans, Tobacoo streak ilarvirus, Tracttus orea
Africa: South Africa; Asia: China, India, Iran, Japan; Europe: Denmark, France, Italy, Netherlands, Russia, Serbia, Slovenia, UK; North America: USA; Oceania: Australia, New Zealand; South America: Venezuela
CA, CO, FL, GA, ID, IA, IL, KS, KY, MA, MI, MN, NC, NJ, NY, OH, OK, OR, PA, WA, WI
Korea, Thailand
2025-08-19
Tobacco streak virus is transmitted mainly through infected pollen carried by thrips and by mechanical means. Seed transmission has been reported but occurs inconsistently, making it a minor but possible pathway depending on the host.
Extensive host range includes many weeds, fruit and ornamental plant species. Over 70 species reported as hosts. The vegetables and agronomic crops listed below are important hosts of Tobacco streak virus
No
TSV000-2, TSV000-3, CABI CPC, DPV WEB, TSV000-15, TSV000-16
Seed as a pathway is not known to occur.
TSV000-2, TSV000-3, CABI CPC, DPV WEB, TSV000-15, TSV000-16
Sdoodee R, Teakle DS, 1988. Seed and pollen transmission of tobacco streak virus in tomato (Lycopersicon esculentum cv. Grosse Lisse). Australian Journal of Agricultural Research, 39:469-474
Kaiser, WJ; Wyatt, SD; Klein, RE, 1991. Epidemiology and Seed Transmission of Two Tobacco Streak Virus Pathotypes Associated with Seed Increases of Legume Germ Plasm in Eastern Washington. Plant Disease 75:258-264
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Description of Plant Viruses ; http://dpvweb.net/dpv/
Vemana, K. and Jain, R.K. (2010). New experimental hosts of Tobacco streak virus and absence of true seed transmission in leguminous hosts. Indian Journal of Virology 21:117-127.
McDaniel, L.L., Raid, R.N., Elliott, C.L.,Tsai, J.H. and Nagata, T. (1992). Purification and serological characterization of a Tobacco Streak Virus Isolate infecting field-grown escarole and lettuce. Plant Disease 76, 966-971.
Tomato black ring virus
virus
Lettuce Ringspot Virus, Bean Ringspot Virus, Beet Ringspot Virus, Celery Yellow Vein Virus, Lettuce Ringspot Virus,Potato Bouquet Virus, Potato Pseudo-Aucuba Virus,Tomato Black Ring Nepovirus
Asia: India, Japan, Saudi Arabia, Turkey; Europe: Albania, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czechia, Finland, France, Germany, Greece, Hungary, Ireland, Lithuania, Moldova, Netherlands, Norway, Poland, Russia, Serbia, Slovakia, Switzerland, Ukraine, UK
Not known to occur
China, Korea, Mexico, Thailand
2025-08-18
Tomato black ring virus spreads by sap contact, pollen, and seed, with seed transmission confirmed in many crops. Soil nematodes also vector it, though efficiency is low, and the spread in fields is patchy. Seed transmission is the main route for long-distance dispersal and survival between seasons.
Wide host range; however, many are experimental only.
Main: onion, leek, garlic, chive, celery, sugarbeet, cabbage, cauliflower, turnip, pepper, cucumber, lettuce, ryegrass, alfalfa, parsley, tomato, potato, spinach, cowpea.
uncertain
TBRV00-2, TBRV00-3, TBRV00-4, TBRV00-11, TBRV00-12
Older literature (TBRV00-2, TBRV00-3) lists seed as a possible pathway, but no evidence of seed transmission was presented for this host. Clear evidence of natural seed transmission was not found.
TBRV00-2, TBRV00-3, TBRV00-4, TBRV00-11, TBRV00-12
Lister RM, Murant AF, 1967. Seed-transmission of nematode-borne viruses. Annals of Applied Biology, 59:49-62.
Murant AF, Lister RM, 1967. Seed-transmission in the ecology of nematode-borne viruses. Annals of Applied Biology, 59:63-76.
Murant AF, 1983. Seed and pollen transmission of nematode-borne viruses. Seed Science and Technology, 11:973-987.
Davis, R.M., Subbarao, K.V., Raid, R.N., and Kurtz, E.A. (1997). Compendium for lettuce diseases. American Phytopathological Society: St. Paul, Minnesota (USA).
Koike, S.T., Gladders, P. and Paulus, A.O. (2007). Vegetable Diseases: A color handbook. Academic Press: Burlington, MA, 451pp.
Pseudomonas syringae pv aptata
bacterium
Bacterium aptatum, Chlorobacter aptatus, Phytomonas aptata, Pseudomonas aptata
Asia: Georgia, India, Iran, Japan, North Korea, South Korea; Europe: Hungary, Italy, Russia, Serbia, UK; North America: USA; Oceania: Australia, New Zealand.
CA, GA, ME, OH, OR, PA, UT, VA, WA
China
2024-09-09
Pseudomonas syringae pv. aptata is spread through rain and irrigation. During cultivation it can be transmitted by workers and tools. It is not known to be seedborne.
Main: sugarbeet, pepper, cucumber, sunflower, lettuce, common bean, eggplant, nasturtium, faba bean, cowpea. Other: melon.
No
No references found indicating seed is a pathway.
Rhodococcus fascians
bacterium
Corynebacterium fascians, Bacterium fascians, Phytomonas fascians, Pseudobacterium fascians, Rhodococcus rubropertinctus
Europe, North America, Central America, Australia, New Zealand, Iran, Russia, Egypt, Colombia
Widespread
Brazil, Thailand
2023-08-21
Though found in many US states, the pathogen is usually restricted and localized. Probably Worldwide, though not reported. Disease outbreaks are sporadic and usually related to poor sanitation. Bulbs, floral and greenhouse crops most susceptible to disease outbreaks. No reports of seed as a pathway in vegetables and agronomic crops.
Primarily a pest of ornamentals, woody ornamentals and floowers. Vegetables and agronomic crops reported susceptible to the bacterium are listed below. Transmits primarily through propagation.
No
CORBFA-2
Lettuce may be a host for this pathogen, though not common. No references found indicating seed is a pathway.
CORBFA-2
International Seed Federation Regulated Pest List Database. pestlist.worldseed.org Nyon Switzerland
Candidatus phytoplasma asteris
phytoplasma
Aconitum proliferation, Aconitum virescence, Alberta aster yellows, alfalfa stunt, Alstroemeria decline, American aster yellows, Anemone virescence, apple sessile leaf, apricot chlorotic leaf roll, azalea little leaf, banana elephantiasis, basil little leaf, Bermuda grass white leaf, black currant reversion, black pepper yellows, blueberry stunt, broccoli phyllody, Bunias phyllody, cactus virescence, cactus witches'-broom, Calendula virescence, canola yellows, Cardaria phyllody, carrot proliferation, carrot yellows, cassava phyllody phytoplasma, cassava witches' broom, Catharanthus little leaf, Catharanthus virescence, chayote witches'-broom, cherry bunch leaf, cherry little leaf, chlorantie, Chrysanthemum witches'-broom, Chrysanthemum yellows, Cirsium stunt, Cirsium yellows, clover phyllody, columbine virescence, coorg black pepper yellows, cosmos phyllody, Cyclamen virescence, dandelion yellows, Delphinium virescence, dill yellows, Diplotaxis virescence, dogfennel yellows, dogwood stunt, dwarf western aster yellows, eastern aster yellows, Echinacea phyllody, eggplant dwarf, eggplant little leaf, Epilobium phyllody, Erigeron yellows, European aster yellows, false ragweed, Festuca yellows, Gaillardia yellows, Gladiolus virescence, grapevine yellows, grey dogwood stunt, hyacinth yellows, Hydrangea phyllody and virescence, Ipomoea obscura witches' broom, Italian cabbage yellows, Italian lettuce yellows, kale phyllody, larkspur virescence, lazy daisy yellows, lettuce yellows, lilac little leaf, Limonium proliferation, Limonium yellows, Lotus yellows, maize bushy stunt, mallow yellows, marguerite yellows, marigold phyllody, marigold virescence, Maryland aster yellows, Mitsuba witches' broom, monarda yellows, mulberry dwarf, multiplier disease, New England aster yellows, New Jersey aster yellows, oat proliferation, Oenothera virescence, olive witches'-broom, onion phyllody, onion virescence, onion yellows, Papaver virescence, parsley yellows, Paulownia witches' broom, peach red leaf disease, pear proliferation and decline, periwinkle little leaf, periwinkle witches' broom and virescence, periwinkle yellows, Phytoplasma asteris, plantain virescence, Poa stunt, poplar witches' broom, poplar yellows, Portulaca yellows, potato purple top, prickly lettuce yellows, Primula yellows, pumpkin yellows, purple coneflower yellows, Quercus proliferation, ragweed yellows, Ranunculus phyllody, rape phyllody, rape virescence, rose witches'-broom, ryegrass yellows, safflower phyllody, Salix proliferation, sandal spike, Saponaria proliferation, Schizanthus proliferation, severe western aster yellows, soybean purple stem, Spirea stunt, Stellaria yellows, strawberry green petal, strawberry phylloid fruit, strawberry stunting, Symphytum proliferation, Tacaco witches'-broom, Tagetes witches' broom, Thalictrum proliferation, tomato big bud, tomato yellows, turnip virescence, Veronica phyllody, watercress witches'-broom, western aster yellows, wild radish yellows
Worldwide
Widespread
-
2024-11-09
Candidatus Phytoplasma asteris is naturally transmitted by a wide range of leafhopper, Macrosteles fascifrons is reported to be the principal vector. Seed is not a pathway.
Wide host range, primarily herbaceous dicots, though strains infect monocots and woody ornamentals
No
CABICPC, ISFRPLD
Seed is not a known pathway.
CABICPC, ISFRPLD
Mycocentrospora acerina
fungus
Centrospora acerina, Cercospora acerina
China, Japan, Chile, Bulgaria, France , Netherlands, Norway, Sweden, United Kingdom
WA, AK, CA, GA, NC
Brazil, China
2022-04-13
celery, carrot, lettuce, caraway. Weeds are common hosts
No
MYCCAC-5, mycc
Seed is not known to be a pathway. No references found indicating seed is a pathway.
MYCCAC-5, mycc
Verticillium albo-atrum
fungus
Verticillium albo-atrum var. caespitosum
Verticillium albo-atrum var. tuberosum
Worldwide, primarily in cool temperate climates and in potato producing areas
Widespread, especially in northern states
China, Thailand
2025-09-15
Verticillium albo-atrum is a soilborne fungal pathogen that causes Verticillium wilt in a wide range of host plants, including vegetables, ornamentals, and woody crops. The fungus invades the plant through the roots, colonizes the vascular system, and disrupts water transport. It survives in soil for many years as microsclerotia, making management difficult. The pathogen is primarily spread through infested soil, plant debris, and infected planting material, but seed transmission has been reported (and unverified) in older reports for some crops.
Main: cauliflower. broccoli, lucerne, tomato, potato; Other: brussel sprouts, cucumber
Not a host
VERTAA-9, CABI CPC, VERTAA-15, VERTAA-17
No references found indicating that lettuce seed is a pathway.
VERTAA-9, CABI CPC, VERTAA-15, VERTAA-17
Richardson, MJ. 1990. Annotated List of Seedborne Diseases, Fourth Ed. International Seed Testing Association. Zurich, Switzerland
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Koike, S.T., Subbarao, K.V., Davis, R.M., Gordon, T.R. and Hubbard, J.C. (1994). Verticillium wilt of cauliflower in California. Plant Disease 78: 1116-1121.
Vallad, G.E., Qin, Q.M., Grube, R., Hayes, R.J. and Subbarao, K.V. (2006). Characterization of race-specific interactions among isolates of Verticillium dahliae pathogenic on lettuce. Phytopathology 96, 1380-1387.
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.
Yes
VERTDA-26, VERTDA-3, VERTDA-5, VERTDA-38, VERTDA-39, VERTDA-40
Verticillium dahliae is a ubiquitous soilborne fungus with a wide host range. Seedborne transmission was shown experimentally under greenhouse conditions, however, the role of seed as a pathway in the epidemiology of the disease has limited importance. The impact of other sources in proximity to lettuce and seed infection of nearby weeds has been shown to be a more important aspect of the disease epidemiology.
VERTDA-26, VERTDA-3, VERTDA-5, VERTDA-38, VERTDA-39, VERTDA-40
Blotter Incubation
VERTDA-3
This method has not been validated or standardized
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.
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.
Atallah, Z.K., Hayes, R.J. and Subbarao, K.V. (2011). Fifteen years of Verticillium wilt of lettuce in America's salad bowl: A tale of immigration, subjugation, and abatement. Plant Disease, 95, 795.
Koike, S.T., Gladders, P. and Paulus, A.O. (2007). Vegetable Diseases: A color handbook. Academic Press: Burlington, MA, 451pp.
Subbarao, K.V. (2013). Biology and epidemiology of Verticillium wilt of lettuce. California Leafy Greens Research Program.
Didymella ligulicola
fungus
Mycosphaerella ligulicola, Stagonosporopsis chrysanthemi, Ascochyta chrysanthemi, Phoma chrysanthemi, Phoma ligulicola var. ligulicola, Phoma ligulicola, Stagonosporopsis ligulicola var. ligulicol, Didymella ligulicola var. ligulicola, Stagonosporopsis ligulicola
Africa: Eswatini; Asia: Japan; Europe: Albania, Andorra, Belgium, Bosnia and Herzegovina, Croatia, France, Germany, Ireland, Italy, Liechtenstein, Luxembourg, Malta, Moldova, Monaco, Norway, Romania, San Marino, Serbia, Slovakia, Slovenia, Ukraine, UK; North America: USA; Oceania: Australia, New Zealand, Papua New Guinea.
CT, DE, GA, NJ, OR, RI, SC, VA
China, Korea
2025-09-22
Didymella ligulicola causes leaf spot disease, producing water-soaked, brown to black lesions on leaves that can lead to leaf blighting. It survives in plant debris or soil and spreads primarily through water-splashed spores. Infection is favored by cool, wet, or humid conditions, and repeated cycles can occur during the growing season. Seed is not known to be a pathway for any host.
Main: chrysanthemum. Other: lettuce, sunflower, chicory, globe artichokes
No
MYCOLG-2, CABI CPC, MYCOLG-3
Seed is not known to be a pathway.
MYCOLG-2, CABI CPC, MYCOLG-3
Hahn W, Schmatz R, 1980. Diagnosis and control of infection by Ascochyta in chrysanthemums. Nachrichtenblatt fur den Pflanzenschutz in der DDR, 34:189-192
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
EFSA Panel on Plant Health (PLH). (2013). Scientific opinion on the risks to plant health posed by Stagonosporopsis chrysanthemi (Stevens) Crous, Vaghefi and Taylor [Didymella ligulicola (Baker, Dimock and Davis) Arx var. ligulicola; syn. Didymella ligulicola (Baker, Dimock and Davis) Arx] in the EU territory, with identification and evaluation of risk reduction options. EFSA Journal, 11(10), 3376.
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.
uncertain
TRSV00-6, CABI CPC, DPV WEB, TRSV00-11
Tobacco ringspot virus is primarily vectored by dagger nematodes. Seed transmission in lettuce is uncertain as reports of this pathway come only from artificially inoculated plants in controlled studies, with no evidence of natural seed transmission. Mechanical spread is possible.
TRSV00-6, CABI CPC, DPV WEB, TRSV00-11
Grogan, RG, and Schnathorst, WC, 1955. Tobacco ringspot virus-The cause of lettuce calico. Plant Disease Reporter 39: 803-806
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Description of Plant Viruses ; http://dpvweb.net/dpv/
Iizuka N, 1973. Seed transmission of viruses in soybean. Bulletin of the Tohoku National Agricultural Experiment Station. 46:131-141.
Broad bean wilt virus
virus
Broad bean wilt fabavirus, Catalpa chlorotic leaf spot virus, Nasturtium ringspot virus, Nasturtium white spot virus, Pea streak virus, Patchouli mild mosaic virus, Patchouli mild mottle virus, Petunia ringspot virus, Tropaeolum ringspot virus, Plantago II virus
Africa: Egypt, Ethiopia, Morocco, South Africa, Sudan, Tanzania, Tunisia; Asia: Bangladesh, China, India, Iran, Iraq, Japan, Jordan, North Korea, Philippines, Singapore, South Korea, Syria, Taiwan, Turkey; Europe: Bulgaria, Czechia, France, Germany, Greece, Hungary, Italy, Poland, Slovakia, Slovenia, Spain, United Kingdom; North America, USA; Oceania: Australia, New Zealand; South America: Argentina.
FL, MN, NY, OH, SC, VT, WI
Mexico
2024-09-03
Broad bean wilt virus has only shown possible seed transmission in faba beans through artificial inoculation. It is not known to be common in nature. The virus is transmissible by sap inoculation and by several aphid species in the non-persistent.
Broad bean wilt virus has been reported in natural infections of 180 species of 41 plant families and thus has a very extensive natural host range. Main host families are: Apiaceae, Brassicaceae, Fabaceae, and Solanaceae.
No
CABICPC, DPVWEB
Seed is not known to be a pathway.
CABICPC, DPVWEB
Tomato ringspot virus
virus
blackberry (Himalaya) mosaic virus, Euonymus chlorotic ringspot virus, Euonymus ringspot virus, grape yellow vein virus, grapevine yellow vein virus, Nicotiana 13 virus, peach stem pitting virus, prune brown line virus, Prunus stem pitting virus, red currant mosaic virus, tobacco ringspot virus 2, tomato ringspot nepovirus, ToRSV, winter peach mosaic virus
Africa: Egypt, Nigeria, Togo; Asia: China, India, Iran, Japan, Jodan, Lebanon, Oman, Pakistan, South Korea, Taiwan, Turkey; Europe: Belarus, Croatia, France, Netherlands, Poland, Russia, Slovakia, Spain, UK; North America: Canada, Puerto Rico, USA; Oceania: Fiji, New Zealand; South America: Brazil, Chile, Colombia, Peru, Venezuela.
Widespread
Korea, Mexico, Thailand
2022-11-07
Natural spread is confined to areas where there are moderate to high populations of nematode vectors belonging to the genus Xiphinema. Requires the nematode to spread. Seed transmission only shown in strawberry and raspberry in nature.
Wide host range, primarily ornamentals and fruit trees and berries. Vegetable crops infected are listed below. Not known to infect grains and grasses
No
TORSV0-2, TORSV0-5
No references found indicating lettuce is infected by this virus
TORSV0-2, TORSV0-5
Brunt, AA, Crabtree, K., Dallwitz, MJ, Gibbs, AJ, Watson, L. and Zurcher, EJ. (eds.). Plant Viruses Online: Descriptions and Lists from the VIDE Database, Version: 16th 1997. http://bio-mirror.im.ac.cn/mirrors/pvo/vide/refs.htm
Richardson, MJ, 1990. An Annotated List of Seed-borne Diseases. International Seed Testing Association, Zurich Switzerland
Lettuce mosaic virus
virus
Lactuca virus 1, lettuce, Mosaic potyvirus, lettuce virus 1, Marmor lactucae
Worldwide, where lettuce is grown.
CA, CO, FL, ID, NY, OH, OR, PA, SC, WA, WI
Mexico
2025-09-23
Lettuce mosaic virus causes mottling, stunting, and poor head formation in lettuce, making it one of the most damaging diseases affecting lettuce worldwide. It is primarily transmitted by aphids in a non-persistent manner, mechanically through sap and through infected seed in lettuce.
Main: lettuce, chicory; Other: spinach, pea, endive, chickpea, safflower
Yes
LMV000-3, LMV000-4, LMV000-6, LMV000-7, CABI CPC, DPV WEB, LMV000-16, LMV000-17
Seed as a pathway in lettuce is well documented and accepted.
ELISA
LMV000-3, LMV000-4, LMV000-6, LMV000-7, CABI CPC, DPV WEB, LMV000-16, LMV000-17
ELISA, PCR, Grow out
LMV000-12, LMV000-2, LMV000-5, LMV000-8, NSHS USDA
The NSHS standard test (Lcb 8.2 ) for Lettuce mosaic virus is ELISA.
Indexed and certified seed. Seed production companies utilize a combination of field mitigation and seed testing to control this virus
LMV000-14, LMV000-6
A heat treatment for seed exists but is impractical for large-scale seed treatment. However, it is adviseable to use this on small amounts of seed such as those used by seed companies for increase and breeding purposes.
Zitter, T. Vegetable MD Online. 1984 http://vegetablemdonline.ppath.cornell.edu/factsheets/Viruses_LeafyVege.htm
Dinant S, Lot H, 1992. Lettuce mosaic virus. Plant Pathology, 41:528-542
Grogan RG, 1983. Lettuce mosaic virus control by use of virus-indexed seed. Seed Science and Technology, 11:1043-1049.
Shukla DD, Ward CW, Brunt AA, 1994. The Potyviridae. CAB International, Wallingford, UK; , 516 pp.
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Description of Plant Viruses ; http://dpvweb.net/dpv/
Stangarlin, O., Pavan, M. A., Silva, N. da, 2000 . Occurrence of a new pathotype of lettuce mosaic virus on lettuce in Brazil.Plant Disease, 84 ( 4 ) 490
Fletcher, J. D., France, C. M., Butler, R. C., 2005 . Virus surveys of lettuce crops and management of lettuce big-vein disease in New Zealand.New Zealand Plant Protection, Volume 58, 2005. Proceedings of a conference, Wellington, New Zealand, 9-11 August 2005 . 239 - 244 .
Firmino, A.C.; Krause-Sakate, R.; Pavan, M. A.; da Silva, N.; Hanai, S. M.; Anbo, R. H.; Nietzsche, T.; Le Gall, O. Prevalence of Lettuce mosaic virus - common strain on three lettuce producing areas from São Paulo State. Summa phytopathol. vol.34 no.2 Botucatu Apr./June 2008
Lettuce mosaic virus Seed Health Method Lcb 8.2. 2015. The National Seed Health System, www.seedhealth.org
Kimble KA, Grogan RG, Greathead AS, Paulus AO, House JK, 1975. Development, application, and comparison of methods for indexing lettuce seed for mosaic virus in California. Plant Disease reporter, 59:461-464
Falk BW, Purcifull DE, 1983. Development and application of an enzyme-linked immunosorbent assay (ELISA) test to index lettuce seeds for lettuce mosaic virus in Florida. Plant Disease, 67:413-416
United Stated Department of Agriculture, Animal and Plant Health Protection Service National Seed Health System (USDA-APHIS NSHS) www.seedhealth.org
Walkey DGA, Dance MC, 1979. High temperature inactivation of seedborne lettuce mosaic virus. Plant Disease Reporter, 63:125-129
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
Microdochium panattonianum
fungus
Ascochyta suberosa, Didymaria perforans, Marssonia panattoniana, Marssonia perforans, Marssonina panattoniana
Worldwide, primarily North America, Europe, Australia
AK, CA, FL, ID, MI, NC, OR TX, WA
2022-04-26
The primary inoculum is soilborne
endive, lettuce
No
MARSPA-3, MARSPA-4, MARSPA-5, RICHISTA
Pathway not proven. Seed as a pathway has been evaluated by artificially inoculated seed and seed harvested from infected plants. Neither technique resulted in infected seedlings. Seed as a pathway has been discounted and other sources of inoculum are considered more important in the epidemiology of the disease.
MARSPA-3, MARSPA-4, MARSPA-5, RICHISTA
Yes, Thiram slurry
MARSPA-5
Produce lettuce seed in dry climates where Microdochium panattonianum is not disease problem.
Davis, R.M., Subbarao, K.V., Raid, R.N., and Kurtz, E.A. 1997. Compendium for lettuce diseases. American Phytopathological Society: St. Paul, Minnesota (USA).
Galea VJ, Price TV, 1988. Infection of lettuce by Microdochium panattonianum. Transactions of the British Mycological Society, 91:419-425
International Seed Federation Regulated Pest List Database. www.pestlist.worldseed.org. Nyon, switzerland
Arabis mosaic virus
virus
Arabis mosaic nepovirus, Ash ring and line pattern virus, forsythia yellow net virus, hop nettlehead virus, jasmine yellow blotch virus, raspberry yellow dwarf virus, Rhabarber mosaik virus (rhubarb mosaic virus), rhubarb mosaic virus
Africa: Egypt, South Africa; Asia: India, Iran, Japan, Kazakhstan, Lebanon, Syria, Turkey; Europe: Austria, Belarus, Belgium, Bulgaria, Croatia, Czechia, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Moldova, Netherlands, Norway, Poland, Romania, Russia, Serbia, Slovenia, Spain, Sweden, Switzerland, Ukraine, UK; North America: Canada, Mexico, USA; Oceania: Australia, New Zealand; South America: Chile, Peru
CT, FL, MI, MN, MO, NE, NY, OH, SC
Mexico, China, Korea, Brazil, Thailand
2025-09-11
Arabis mosaic virus is a virus in the genus Nepovirus that infects a wide range of crops. It is transmitted mainly by the nematode Xiphinema diversicaudatum in soil and through infected planting material, with mechanical transmission possible. A heavily cited report from 1967 suggests seed transmission in some species, but no further evidence has been found since.
Wide host range including many vegetable, agronomic and fruit species. Main: celery, asparagus, sugarbeet, cucumber, carrot, lettuce, clover.
uncertain
ARMV00-3, ARMV00-4, ARMV00-5, ARMV00-6, CABI CPC, DPV WEB, ARMV00-10, ARMV00-12
Arabis mosaic virus has been reported on lettuce seed in some surveys, but evidence for natural seed transmission is lacking. Murant lists the virus as seed-borne without presenting supporting data. Mandahar concluded that seed transmission in the field is uncommon. Walkey demonstrated seed transmission only under artificial inoculation conditions, providing no evidence that lettuce seed acts as a pathway in nature; therefore, the role of seed in transmission remains uncertain.
ARMV00-3, ARMV00-4, ARMV00-5, ARMV00-6, CABI CPC, DPV WEB, ARMV00-10, ARMV00-12
Murant. 1983. Seed and Pollen Transmission of Nematode-borne viruses. Seed Sci and Technol. 11:973-987
Mandahar, CL. 1981. Virus Transmission through seed and pollen. In, Plant Diseases and Vectors, Maramorosch, K and Harris, KF, ed. Acedemic Press.
Lister and Murant. 1967. Seed-transmission of nematode-borne viruses. Annals of Applied Biology, 59:49-62.
Walkey, 1967. Seed Transmission of Arabis Mosaic Virus in Lettuce (Lactuca sativa). Plant Dis. Rept. 883-884
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Description of Plant Viruses ; http://dpvweb.net/dpv/
Baker, R., Bragard, C., Candresse, T., Gilioli, G., Grégoire, J. C., Holb, I., ... & van der Werf, W. (2013). Scientific opinion on the risk to plant health posed by Arabis mosaic virus, Raspberry ringspot virus, Strawberry latent ringspot virus and Tomato black ring virus to the EU territory with the identification and evaluation of risk reduction options. EFSA JOURNAL, 11(10), 1-83.
Mossop, D. W., Fry, P. R., & Young, B. R. (1983). New plant disease records in New Zealand: arabis mosaic virus in celery, lettuce, and Chinese cabbage; tomato spotted wilt virus in celery. New Zealand journal of agricultural research, 26(2), 257-259.
Beet western yellows virus
virus
Brassica virus 5, Malva yellows virus, Radish yellows virus, Turnip mild yellows virus, Turnip yellows virus luteovirus
Africa: Eritrea, Ethiopia, Tunisia; Asia: China, Iran, Iraq, Israel, Japan, Lebanon, Pakistan, South Korea, Syria, Thailand, Turkey, Yemen; Europe: Czechia, France, Germany, Greece, Italy, Spain, UK; North America: USA; Oceania: Australia, New Zealand.
CA, IL, OR, WA
Korea
2024-08-21
Transmission is by aphid vectors, particularly the green peach aphid.
Main: Brassica spp., radish, spinach. Other: sugarbeet, chickpea, pepper.
No
BWYV00-3, CABICPC, ISFRPLD, DPVWEB
Seed is not known to be a pathway.
BWYV00-3, CABICPC, ISFRPLD, DPVWEB
Impatiens necrotic spot virus
virus
Tomato spotted wilt tospovirus, Impatiens strain
Africa: Egypt, Uganda; Asia: China, Iran, Japan, South Korea; Europe: Belgium, Bosnia and Herzegovina, Bulgaria, Czechia, Finland, France, Germany, Greece, Gurnsey, Hungary, Italy, Lithuania, Netherlands, North Macedonia, Poland, Portugal, Serbia, Slovenia, Spain, Sweden, UK; North America: Canada, Costa Rica, Guatemala, Mexico, Panama, USA; Oceania: Australia, New Zealand; South America: Chile, Colombia.
Widespread
Korea
2024-09-07
The virus is closely related to Tomato spotted wilt virus and a member of the Tospovirus group of viruses which are thrip transmitted. Seed transmission is unlikely and not reported for any host.
Wide host range. Main: Impatiens. Other: many ornamentals and vegetables.
No
INSV00-2, CABICPC, ISFRPLD
Seed is not known to be a pathway.
INSV00-2, CABICPC, ISFRPLD
Difficult to control. Field control must consider the virus and the vector for success.
Tobacco rattle virus
virus
Aster ringspot virus, belladonna mosaic virus, paeony mosaic virus, paeony ringspot virus, peony mosaic virus, peony ringspot virus, potato corky ringspot virus, potato stem mottle virus, ratel virus, spinach yellow mottle virus, Tabakmauche Virus, Tabakstreifen und Kra, tobacco rattle tobravirus, tulip white streak virus
Worldwide
AK, CA, CO, FL, ID, IL, IN, MA, MI, MN, NE, NC, ND, OH, OR, PA, UT, WA, WI
Korea
2024-09-08
Tobacco Rattle Virus is soil-borne and transmitted between plants by the nematode species Trichodorus and Paratrichodorus. Seed is only known to be a pathway in some weed species.
TRV occurs on numerous crops in many countries and has been detected on over 100 mono- and dicotyledonous plant species.
No
CABICPC, ISFRPLD, RICHISTA
Lettuce is a known host of Tobacco rattle virus, though disease problems are rare. No references found indicating seed is a pathway.
CABICPC, ISFRPLD, RICHISTA
Pseudomonas syringae pv. syringae
bacterium
Many
Worldwide
Widespread
Thailand, China, Korea
2022-12-01
Seed is known to be a pathway on several crops. Thailand lists this pathogen as prohibited on corn. China lists this pathogen (Pseudomonas oryzicola) as prohibited on rice.
Wide host range. Important vegetable and agronomic crops listed below.
No
PSDMSY-2
No references found indicating lettuce is a host for this pathogen.
PSDMSY-2
International Seed Federation Regulated Pest List Database. pestlist.worldseed.org Nyon, Switzerland
Pseudomonas cichorii
bacterium
Bacterium cichorii, Bacterium endiviae, Bacterium formosanum, Chlorobacter cichorii, Phytomonas cichorii, Phytomonas endiviae, Pseudomonas endiviae, Pseudomonas formosanum, Pseudomonas papaveris, Pseudomonas papaveris
Worldwide
AL. CA, FL, GA. HI, IL, IN, LA, MS, T. MJ, NY, NC, PA, TN, WA
Thailand
2025-10-06
Pseudomonas cichorii is a Gram-negative bacterium that causes leaf spot, blight, and rot on many crops such as lettuce and celery. It thrives in cool, moist environments and spreads mainly through splashing water, rain, or contaminated tools and hands. It survives on plant surfaces and debris. Transmission is favored by high humidity and overhead irrigation, leading to rapid spread and characteristic brown, water-soaked leaf lesions.
Main: celery, endives, chicory, lettuce, adzuki bean; Other: numerous in the Asteraceae and Brassicaceae families.
No
PSDMCI-3, PSDMCI-4, PSDMCI-5, PSDMCI-6, PSDMCI-7, PSDMCI-8, PSDMCI-9, PSDMCI-10
For lettuce, Pseudomonas cichorii has been shown to survive on artificially inoculated seeds, but there is no experimental evidence confirming true seed transmission under natural conditions. While some sources have suggested seed as a possible pathway, others deny it. Lettuce seed is typically produced in dry climates, which are unfavorable for the pathogen’s survival, further reducing risk. Infections in production fields are more likely initiated from splashing water, irrigation, or contaminated debris rather than seed.
PSDMCI-3, PSDMCI-4, PSDMCI-5, PSDMCI-6, PSDMCI-7, PSDMCI-8, PSDMCI-9, PSDMCI-10
Seed wash
CABI CPC
This test is commercially available, however the test has not been standardized or validated.
Cultural
CABI CPC, PSDMCI-9
Seed production in dry climates are unfavorable for this pathogen. Only cultural controls in the field are effective (irrigation control, plant density, weed control, etc.)
Ohata, K.I., Tsuchiya, Y. and Shirata, A. (1979). Difference in kinds of pathogenic bacteria causing head rot of lettuce of different cropping types. Annals of the Phytopathogenic Society of Japan 45, 333-338.
Pernezny K, Datnoff L, Sommerfeld ML, 1994. Brown stem of celery caused by Pseudomonas cichorii. Plant Disease, 78(9):917-919
Grogan RG, Misaghi IJ, Kimble KA, Greathead AS, Ririe D, Bardin R, 1977. Varnish spot, destructive disease of lettuce in California caused by Pseudomonas cichorii. Phytopathology, 67(8):957-960
Patel, N., Patel, R., Wyenandt, C. A., 2021. First report of Pseudomonas cichorii causing bacterial leaf Spot on romaine lettuce (Lactuca sativa var. longifolia) and escarole (Cichorium endivia) in New Jersey.Plant Disease, 105(12) 4150-4150.
Aysan, Y., Sahİn, S., Ulke, G., Sahİn, F., 2003. Bacterial rot of lettuce caused by Pseudomonas cichorii in Turkey.Plant Pathology, 52(6) 782.
Patterson, C.L., Grogan, R.G. and Campbell, R.N. (1986). Economically Important diseases of lettuce. Plant Disease 70, 982-987.
Bazzi, C., Piazza, C., & Mazzucchi, U. (1984). Survival in the Field of Pseudomonas cichorii (Swingle) Stapp, Causal Agent of Lettuce Varnish Spot*. Journal of Phytopathology, 111(3‐4), 251-258.
Shirata, A., Ohata, K., Serizawa, S. and Tsuchiya, Y. (1982). Relationship between the lesion development by Pseudomonas cichorii and growth stage and leaf position of lettuce and its infection mechanism. Bull. Natl. Inst. Agric. Sci. C36: 61-74
Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Tomato infectious chlorosis virus
virus
Tomato infectious chlorosis closterovirus
Asia, Tunisia, Europe, Mexico
Reported in CA, NC
Korea
2022-09-21
Whitefly transmitted virus. Phloem limited Criniviruses are not known to be seed transmitted. Not to be confused with Tomato chlorosis virus, a closely related Crinivirus.
tomato, potato, petunia
No
TICV00-2
Lettuce has been identified as an occasional host, but references confirming this have not been found. No references found indicating seed is a pathway. Seed transmission is not known to occur in Criniviruses or other members of the Closteroviridae family.
TICV00-2
International Seed Federation Regulated Pest List Database. www.pestlist.worldseed.org
Septoria lactucae
fungus
Ascochyta lactucae, Septoria lactucicola, Septoria consimilis
Worldwide
Widespread
Korea
2025-08-01
Septoria lactucae spreads primarily through rain splash that moves spores from infected debris or nearby plants onto healthy leaves. It can survive on seed and wild hosts; however, most infections occur in wet conditions when spores are dispersed from contaminated crop residues.
Main: lettuce
Yes
SEPTLA-1, SEPTLA-2, SEPTLA-3, SEPTLA-4
Seed as a pathway is well established and accepted.
SEPTLA-1, SEPTLA-2, SEPTLA-3, SEPTLA-4
Blotter Incubation; Seed wash and visual examination
SEPTLA-1
These tests have not been standardized or validated.
Hot water treatment
SEPTLA-1, SEPTLA-2
Seed production in arid climates with little rainfall limit the risk of Septoria contamination.
International Seed Federation Regulated Pest List Database. www.pestlist.worldseed.org. Nyon, switzerland
Koike, ST. 2017. In, Compendium of Lettuce Diseases, Subbarao KV, Davis RM, Gilbertson RL and Raid RN, eds. APS Press, St. Paul MN USA
Kim BR, Choi YJ and Shin HD. 2019. First Report of Leaf Spot Caused by Septoria lactucae in Lactuca serriola (prickly lettuce) in Korea. Plant Dis. 104; 581
Cabral, C.S., Fonseca, M.E.N., Boiteux, L.S. et al. Phenotypic and genetic variability of fungal isolates associated with the Septoria leaf spot disease of lettuce (Lactuca sativa) in Brazil. J Plant Dis Prot 129, 53–62 (2022).
Nacobbus aberrans
nematode
Anguillulina aberrans, Nacobbus batatiformis, Nacobbus bolivianus, Nacobbus serendipiticus, Nacobbus serendipiticus bolivianus, Pratylenchus aberrans
Egypt, Argentina, Bolivia, Chile, Ecuador, Peru, Mexico
AR, CO, KS, MT, NE, SD, UT, WY
Korea
2023-08-21
Seed is not known to be a pathway for this nematode in any host.
potato, vegetables
No
NACOBA-1, NACOBA-2
Seed is not known to be a pathway for this nematode in any host.
NACOBA-1, NACOBA-2
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
uncertain
ALTEAL-26, ALTEAL-27, ALTEAL-4, ALTEAL-29
Alternaria alternata has been reported on lettuce, but is generally not considered a pathogen of this crop. The fungus has been detected on lettuce seed in laboratory surveys; however, no evidence was found confirming seed transmission. A. alternata is not listed as a pathogen in the most recent version of the Compendium of Lettuce Diseases and Pests (ALTEAL-27). Given the lack of verified field evidence, the seed pathway for A. alternata is uncertain.
ALTEAL-26, ALTEAL-27, ALTEAL-4, ALTEAL-29
Blotter incubation
ALTEAL-26
Blotter incubation was used in surveys. This method has not been standardized or validated.
ALTEAL-1
Seed treatments affective against A. alternata have been described for other hosts.
Muniz, PH, Marques, MG, Peixoto, GHS, Simão, KG and Carvalho, DDC. 2018. Morphological characterization of Alternaria alternata associated on iceberg lettuce seeds cv. 'Astra'. Revista de Agricultura Neotropical 5:82-86
Subbarao KV, Davis RM, GilbertsonRL, and Raid RN. 2017. PART I: Infectious Diseases. Compendium of Lettuce Diseases and Pests, Second Edition. The American Phytopathological Society, St. Paul, MN, USA
Richardson MJ, 1990. An Annotated List of Seed-borne Disease. International Seed Testing Association, Zurich, Switzerland
Chen W and Hoáubowicz R. 2010. Effect of Treating Lettuce (Lactuca sativa L.) Seeds with Solutions of Ethereal Oils From Camphor Tree (Cinnamomum camphora L.) and Patchouli Plant (Pogostemon cablin Benth.) on Their Germination. Acta Sci. Pol., Hortorum Cultus 9: 69-83
Alternaria alternata. In: Crop Protection Compendium. Wallingford, UK: CAB International. www.cabi.org/cpc.
Lettuce big-vein virus
virus
Lettuce big vein-virus
Asia: China, Israel, Japan, Saudi Arabia, Turkey; Europe: Belgium, France, Germany, Greece, Italy, Netherlands, Poland, Sweden, United Kingdom; North America: Bermuda, Mexico, USA; Oceania: Australia, New Zealand; South America: Brazil, Chile, Colombia.
AZ, CA, FL
Korea
2024-12-15
Not considered a quarantine pest. Transmitted by the Olpidium brassicae fungus.
Main: lettuce; Other: endive
No
CABICPC
There is no evidence that this virus is seed borne. Vectored by the Olpidium brassicae fungus.
CABICPC
Alfalfa mosaic virus
virus
Alfalfa virus 1 and 2, Lucerne mosaic virus, Marmor medicaginis, Potato calico virus, Tomato necrotic tip curl, Alfalfa yellow spot
Worldwide
Widespread
Sudan, Mexico
2022-09-13
Wide host range
No
ISFRPLD, AMV000-9
Lettuce is an infrequent host of this virus. There is no evidence that seed is a pathway.
ISFRPLD, AMV000-9
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