APPENDIX 5: Crop Disease Pathogens Hosted by Co...

APPENDIX 5: Crop Disease Pathogens Hosted by Common Agricultural Weeds

APPENDIX 5: Crop Disease Pathogens Hosted by Common Agricultural Weeds

Compiled by Charles L. Mohler and Margaret Tuttle McGrath

References (in parentheses) can be checked here.

Weed common name Weed scientific name Pathogens and crop diseases1
Barnyard grass Echinochloa crusgalli (L.) Beauv. Pythium ultimum (seed rot and root rot of pea, beet, and crucifer crops), Fusarium oxysporum (various diseases of many crops), Colletotrichum graminicola (anthracnose of corn), Phoma terrestris (onion pink rot), Rhizoctonia solani (various diseases of many crops) (31); alfalfa dwarf disease (Xylella fastidiosa); viruses including maize dwarf mosaic, barley stripe mosaic hordeivirus, oat pseudorostette tenuivirus, and wheat streak mosaic rymovirus (45).
Bedstraw, catchweed (cleavers) Galium aparine L. No records located for North America.
Bedstraw, smooth Galium mollugo L. No records located.
Bindweed, field Convolvulus arvensis L. Rhizoctonia solani (various diseases of many crops) (31); alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus, potato virus Y potyvirus, tomato spotted wilt tospovirus (128).
Bindweed, hedge Calystegia sepium (L.) R. Br.  
Bluegrass, annual Poa annua L. Septoria nodorum (stagnospora blotch of wheat), Claviceps purpurea (ergot), Gaeumannomyces graminis (take-all), Erysiphe graminis (powdery mildew) (77), but whether the strains that attack annual bluegrass can damage wheat is unclear; Cephalosporium gramineum (cephalosporium stripe) (84); Fusarium sp. (various diseases of many crops), Rhizoctonia solani (various diseases of many crops) (31); barley yellow dwarf virus (48).
Buckwheat, wild Polygonum convolvulus L. Rhizoctonia solani (various diseases of many crops) (31); Meloidogyne hapla (northern root-knot nematode) (113);  tomato spotted wilt tospovirus (128).
Burcucumber Sicyos angulatus L. Cucumber mosaic virus, papaya ring spot potyvirus, watermelon mosaic potyvirus (128).
Campion, white Silene alba (Mill.) E.H.L. Krause Cucumber mosaic cucumovirus, turnip mosaic potyvirus, tobacco mosaic tobamovirus (128).
Chamomile, corn Anthemis arvensis L. Rhizoctonia solani (various diseases of many crops) (31).
Chamomile, mayweed Anthemis cotula L. No records located.
Chickweed, common Stellaria media (L.) Vill. Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop) (31); Phoma exigua var. foveata (potato rot fungus) (77); cucumber mosaic cucumovirus, turnip mosaic potyvirus, bean yellow mosaic potyvirus, potato virus Y potyvirus, tomato spotted wilt tospovirus (128). Many additional viruses affecting crops are reported on common chickweed in the United Kingdom and may be present in North America as well (100).
Chickweed, mouseear Cerastium vulgatum L. Rhizoctonia solani (various diseases of many crops) (31).
Cockle, corn Agrostemma githago L. Fusarium sp. (various diseases of many crops) (31); cucumber mosaic cucumovirus, turnip mosaic potyvirus (128).
Cocklebur, common Xanthium strumarium L. Verticillium alboatrum (verticillium wilt of nightshade crops) (26).
Copperleaf, Virginia Acalypha virginica L. Alternaria spp. (alternaria leaf spot) (37).
Crabgrass, large Digitaria sanguinalis (L.) Scop. Colletotrichum graminicola (anthracnose of corn), Rhizoctonia solani (various diseases of many crops) (31); barley stripe hordeivirus (45); southern root-knot nematode (Meloidogyne incognita) (29).
Dandelion Taraxacum officinale Weber in Wiggers Sclerotinia sclerotiorum (white mold of potato, tomato, beans, cabbage, and carrot, lettuce drop), Rhizoctonia solani (various diseases of many crops) (31); Verticillium alboatrum (verticillium wilt) (26); aster yellow phytoplasma, (46); alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus, turnip mosaic potyvirus, potato virus Y potyvirus (128); dandelion yellow mosaic virus of lettuce (36).
Foxtail, giant Setaria faberi Herrm. No records located.
Foxtail, green Setaria viridis (L.) Beauv. Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop), Exserohilum turcicum (northern corn leaf blight), Fusarium oxysporum (various diseases of several crops), Fusarium solani (fusarium dry rot of potato, fusarium crown and root rot of cucurbits), Stemphylium botryosum (onion stalk rot), Phoma terrestris (onion pink rot), Rhizoctonia solani (various diseases of many crops) (31).
Foxtail, yellow Setaria glauca (L.) Beauv. Claviceps purpurea (ergot), Pythium graminicola (browning root rot), Sclerospora graminicola (downy mildew), Ustilago neglecta (smut) (17).
Galinsoga, hairy Galinsoga ciliata (Raf.) Blake Alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus, turnip mosaic potyvirus (128); several nematodes including Meloidogyne hapla (northern root-knot nematode) and Heterodera schachtii (beet cyst nematode) (77).
Goosegrass Eleusine indica (L.) Gaertn. Colletotrichum graminicola (anthracnose of corn), Rhizoctonia solani (various diseases of many crops) (31); corn dwarf mosaic (45). 
Groundcherry, smooth Physalis subglabrata Mackenz. & Bush Alfalfa mosaic alfamovirus, potato virus Y potyvirus, tobacco etch potyvirus (128).
Groundsel, common Senecio vulgaris L. Verticillium alboatrum (verticillium wilt) (26, 31); alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus, lettuce mosaic virus (128); Meloidogyne hapla (northern root-knot nematode) (113).
Horsenettle Solanum carolinense L. Phoma terrestris (onion pink rot), Septoria lycopersici (septoria leaf spot of tomato) (31); Verticillium alboatrum (verticillium wilt) (26, 31); Phytophthora capsici (phytophthora blight) (35); cucumber mosaic cucumovirus, tobacco etch potyvirus (128).
Horsetail, field Equisetum arvense L. Rhizoctonia solani (various diseases of many crops) (31).
Lambsquarters, common Chenopodium album L. Peronospora effusa (downy mildew of spinach), Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop), Cercospora beticola (cercospora leaf spot of beet), Rhizoctonia solani (various diseases of many crops) (31); clubroot (Plasmodiophora brassicae) (36); Verticillium alboatrum (verticillium wilt) (26); alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus, bean yellow mosaic potyvirus, clover yellow vein potyvirus, potato virus Y potyvirus, soybean mosaic potyvirus, tobacco etch potyvirus, turnip mosaic potyvirus, watermelon mosaic potyvirus, lettuce mosaic virus (128); barley stripe mosaic hordeivirus, beet yellows virus, beet curly top virus (45); beet nematode (Heterodera schachtii) (20); Meloidogyne hapla (northern root-knot nematode) (113); Meloidogyne incognita (southern root-knot nematode) (29).
Lettuce, prickly Lactuca serriola L. Microdochium panattonianum (lettuce anthracnose), Verticillium dahliae (verticillium wilt) (13); Cercospora longissima (cercospora leaf spot), Erysiphe cichoracearum (powdery mildew), and Septoria lactucae (septoria leaf spot of lettuce), Bremia lactucae (downy mildew of lettuce), Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop), Rhizoctonia solani (various diseases of many crops), Sclerotium rolfsii (southern blight) (31); cucumber mosaic cucumovirus, tomato spotted wilt tospovirus (31); Meloidogyne hapla (northern root-knot nematode) (113).
Mallow, Venice Hibiscus trionum L. Rhizoctonia solani (various diseases of many crops) (31).
Medic, black Medicago lupulina L. Rhizoctonia solani (various diseases of many crops) (31); alfalfa mosaic alfamovirus, bean yellow mosaic potyvirus, clover yellow vein potyvirus (128); Meloidogyne hapla (northern root-knot nematode) (113).
Milkweed, common Asclepias syriaca L. Rhizoctonia solani (various diseases of many crops) (31); alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus (128).
Millet, wild-proso Panicum miliaceum L. Pythium ultimum (seed decay and root rot of many crops), Exserohilum turcicum (northern corn leaf blight), Fusarium oxysporum (various diseases of many crops), Colletotrichum graminicola (corn anthracnose) (31).
Morningglory, ivyleaf Ipomoea hederacrea (L.) Jacq. Fusarium sp. (various diseases of many crops) (31).
Morningglory, pitted Ipomoea lacunosa L. Cucumber mosaic cucumovirus (128).
Morningglory, tall Ipomoea purpurea (L.) Roth Cucumber mosaic cucumovirus (128).
Mustard, hedge Sisymbrium officinale (L.) Scop. Peronospora parasitica(downy mildew of crucifer crops) (31).
Mustard, wild Brassica kaber (DC.) L. C. Wheeler (= Sinapsis arvenis L.) Peronospora parasitica (downy mildew of crucifer crops), Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop), Rhizoctonia solani (various diseases of many crops) (31); Cystopus candidus Albugo candida (white blister) (36); Plasmodiophora brassicae (clubroot), Bacterium campestre (77); cucumber mosaic cucumovirus, turnip mosaic potyvirus (128); Meloidogyne hapla (northern root-knot nematode) (113).
 Nightshade, eastern black Solanum ptycanthum Dun. Phytophthora infestans (late blight), Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop), Alternaria solani (early blight), Verticillium albo-atrum (verticillium wilt of solanaceous crops), Colletotrichum coccodes (anthracnose of tomato and eggplant, potato black dot), Rhizoctonia solani (various diseases of many crops) (31); Phytophthora capsici (phytophthora blight) (35); alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus, potato virus Y potyvirus, tobacco etch potyvirus, tomato spotted wilt tospovirus, turnip mosaic potyvirus, watermelon mosaic potyvirus (128).
Nutsedge, yellow Cyperus esculentus L.  Sclerotinia minor on lettuce and peanut (44a and appendix 3); alfalfa mosaic virus (45); Meloidogyne incognita (southern root-knot nematode) (29).
Panicum, fall Panicum dichotomiflorum Michx. No records located.
Pennycress, field Thlaspi arvense L. Verticillium dahliae (verticillium wilt), Peronospora parasitica (downy mildew), Alternaria brassicicola (alternaria leaf spot) (13); Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop) (31); Plasmodiophora brassicae (clubroot) (36, 31); cucumber mosaic cucumovirus, turnip mosaic potyvirus (128); Meloidogyne hapla (northern root-knot nematode) (113); M. incognita (southern root-knot nematode), Pratylenchus penetrans (meadow nematode), Heterodera schachtii (sugar beet cyst nematode), H. glycines (soybean cyst nematode) (11). 
Pepperweed, field Lepidium campestre (L.) R. Br. Plasmodiophora brassicae (clubroot) (36); Phoma terrestris (onion pink rot), Alternaria brassicae (alternaria leaf spot of mustard family crops) (31); Meloidogyne hapla (northern root-knot nematode) (113).
Pepperweed, Virginia Lepidium virginicum L. Plasmodiophora brassicae (clubroot), Alternaria brassicae (alternaria leaf spot of mustard family crops) (31).
Pigweed, Powell amaranth Amaranthus powellii S. Wats. Albugo bliti (white rust), Alternaria spp. (various leaf spots and blights), Fusarium spp. (various wilts and rots) (11).
Pigweed, prostrate Amaranthus blitoides S. Wats. Rhizoctonia solani (various diseases of many crops) (31); alfalfa mosaic alfamovirus, potato virus Y potyvirus, cucumber mosaic cucumovirus, tomato spotted wilt tospovirus (128).
Pigweed, redroot Amaranthus retroflexus L. Albugo bliti (white rust), Alternaria solani (early blight), Choanephora cucurbitarum (choanephora blossom blight and fruit rot of cucurbits), Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop), Sclerotium rolfsii (southern blight), Verticillium albo-atrum (verticillium wilt of nightshades), Verticillium dahliae (verticillium wilt of cucurbits, nightshades), Rhizoctonia solani (various diseases of many crops, Fusarium oxysporum f. sp. betae (fusarium wilt of beet) (11); alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus, tomato spotted wilt tospovirus, turnip mosaic potyvirus (128); Meloidogyne incognita (southern root-knot nematode) (29); Heterodera schachtii (sugar beet cyst nematode), Pratylenchus penetrans (lesion nematode) (11).
Pigweed, smooth Amaranthus hybridus L.  Albugo bliti (white rust), Rhizoctonia solani (various diseases of many crops), Fusarium oxysporum f. sp. radicis-lycopersici (tomato fusarium wilt) (11); alfalfa mosaic alfamovirus, potato virus Y potyvirus (128); tobacco mosaic virus (45); Meloidogyne incognita (southern root-knot nematode) (11).
Pigweed, tumble Amaranthus albus L. Rhizoctonia solani (various diseases of many crops) (11); overwintering host for alfalfa mosaic virus (51); Meloidogyne incognita (southern root-knot nematode), Heterodera schachtii (sugar beet cyst nematode) (11).
Purslane, common Portulaca oleracea L.  Fusarium sp. (various diseases of many crops), Verticillium albo-atrum (verticillium wilt of solanaceous crops), Rhizoctonia solani (various diseases of many crops) (31); Phytophthora capsici (phytophthora blight) (35); aster yellows phytoplasma, clover big vein virus (45); alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus, potato virus Y potyvirus, turnip mosaic potyvirus, tomato spotted wilt tospovirus (128).
Quackgrass Elytrigia repens (L.) Nevski Pythium ultimum (seed rot and root rot of pea, beet, and crucifer crops), Colletotrichum graminicola (anthracnose of corn), Rhizoctonia solani (various diseases of many crops) (31); Gaeumannomyces graminis (take-all) (52).
Radish, wild Raphanus raphanistrum L. Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop), Phoma lingam (black leg and seed decay of crops in the mustard family) (31); Plasmodiophora brassicae (clubroot) (36); cucumber mosaic cucumovirus, turnip mosaic potyvirus (128).
Ragweed, common Ambrosia artemisiifolia L. Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop), Rhizoctonia solani (various diseases of many crops) (31); rusts of wheat, rye, and barley, aster yellows phytoplasma (77)
Rocket, yellow Barbarea vulgaris R. Br. Peronospora parasitica (downy mildew of crucifer crops) (31); Meloidogyne hapla (northern root-knot nematode) (113).
Ryegrass, Italian Lolium multiflorum Lam. Colletotrichum graminicola (corn anthracnose), Rhizoctonia solani (various diseases of many crops) (31); Claviceps purpurea (ergot), barley yellow dwarf virus, oat sterile dwarf virus (6).
Shattercane Sorghum bicolor (L.) Moench Pythium ultimum (seed decay and root rot of several crops), Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop), Fusarium oxysporum (various diseases of several crops), Phoma terrestris (onion pink rot), Rhizoctonia solani (various diseases of many crops) (31); Peronosclerospora sorghi (sorghum downy mildew of corn) (123).
Shepherd's purse Capsella bursapastoris (L.) Medicus Plasmodiophora brassicae (clubroot) and Cystopus candidus Albugo candida (white blister), which attack most crops in the mustard family, Rhizoctonia solani (black scurf and stem canker of potato) (36); Xanthomonas campestris pv. campestris (bacterial wilt), Peronospora parasitica (black rot and downy mildew of crops in the mustard family) (31); aster yellows phytoplasma (45); viruses including alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus, turnip mosaic potyvirus, tomato spotted wilt tospovirus, watermelon mosaic potyvirus (128); aster yellows phytoplasma, beet curly top hybrigeminivirus, beet mosaic potyvirus, beet yellows closterovirus, cauliflower mosaic virus (45); Meloidogyne hapla (northern root-knot nematode) (113).
Sida, prickly Sida spinosa L. Verticillium albo-atrum (verticillium wilt) (26).
Smartweed, Pennsylvania Polygonum pensylvanicum L. No records located.
Sowthistle, annual Sonchus oleraceus L. Bremia lactucae (lettuce downy mildew), Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop) (31); aster yellows phytoplasma, beet curly top hybrigeminivirus (45); alfalfa mosaic alfamovirus, cucumber mosaic cucumovirus, tomato spotted wilt tospovirus, lettuce mosaic virus (128).
Sowthistle, perennial Sonchus arvensis L. Bremia lactucae (downy mildew of lettuce). Diseased roots can act as a source of Fusarium oxysporum (various diseases of many crops), Rhizoctonia solani (various diseases of many crops), and Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop); aster yellows phytoplasma (12).
Speedwell, corn Veronica arvensis L. Cucumber mosaic cucumovirus (128).
Speedwell, Veronica persica Arabis mosaic and strawberry latent ring spot viruses carried by the nematode Xiphinema diversicaudatum (111).
Thistle, Canada Cirsium arvense (L.) Scop. Sclerotinia sclerotiorum (white mold and cottony rot of potato, tomato, beans, cabbage, and carrot; lettuce drop) (31); rusts of rye and barley (77); cucumber mosaic cucumovirus, bean yellow mosaic potyvirus, turnip mosaic potyvirus (128); aster yellows phytoplasma (76); Meloidogyne hapla (northern root-knot nematode) (113).
Velvetleaf Abutilon theophrasti Medicus Phomopsis sojae (pod and stem blight of soybean), Colletotrichum dematium and C. gloeosporioides (soybean anthracnose), Verticilium dahliae (verticillium wilt) (12); Colletotrichum coccodes (tomato anthracnose and potato black dot), C. gloeosporioides (pepper anthracnose) (31); Phytophthora capsici (phytophthora blight) (29); Meloidogyne hapla (northern root-knot nematode) (12); turnip mosaic potyvirus (128).
Violet, field Viola arvensis Murr. No records located
Witchgrass Panicum capillare L. Fusarium oxysporum (various vegetable diseases), Colletotrichum graminicola (corn anthracnose), Phoma terrestris (onion pink rot), Rhizoctonia solani (various diseases of many crops) (31); wheat streak mosaic rymovirus, barley yellow dwarf luteovirus, barley stripe mosaic hordeivirus, maize chlorotic mottle machlomovirus, maize dwarf mosaic potyvirus, sugarcane mosaic potyvirus, wheat American striate mosaic nucleorhabdovirus; also susceptible to bromegrass mosaic virus but whether it hosts this virus in the field is unknown (13).
Woodsorrel, yellow Oxalis stricta (L.) Sexual stages of Puccinia sorghi and P. polysora (corn rusts) and P. purpurea (sorghum rust) (11).
Yellowcress, marsh Rorippa islandica (Oeder) Borbas Plasmodiophora brassicae (clubroot), Peronospora parasitica (downy mildew of crucifer crops) (31); cucumber mosaic cucumovirus (128).

Notes:

1 Both common and scientific names are given where possible.  Note that diseases with the same common name are sometimes caused by different organisms in different crops (for example, downy mildew), and the weed may only host one of the pathogens with that common name.

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