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Diseases of Alfalfa
(Medicago sativa L.)

D. A. Samac, L. H. Rhodes, and W. O. Lamp, primary collators (Last update: 6/25/14)

BACTERIA AND PHYTOPLASMAS

Alfalfa witches’-broom
‘Candidatus Phytoplasma asteris’
‘Candidatus Phytoplasma aurantifolia’
‘Candidatus Phytoplasma fraxini’
Australian lucerne yellows
‘Candidatus Phytoplasma aurantifolia’
‘Candidatus Phytoplasma australiense’
Bacterial leaf spot
Xanthomonas alfalfae subsp. alfalfae (ex Riker et al. 1935) Schaad et al. 2007
          (syn. Xanthomonas campestris pv. alfalfae (Riker et al.) Dye)
Bacterial stem blight
Pseudomonas syringae pv. syringae van Hall
Bacterial wilt
Clavibacter michiganensis subsp. insidiosus (McCulloch) Davis et al.
          (syn. Clavibacter michiganense subsp. insidiosum (McCull.) Davis et al.)
Crown gall
Agrobacterium tumefaciens (Smith & Townsend) Conn
Dwarf
Xylella fastidiosa subsp. fastidiosa Wells et al. 1987
Sprout rot
Dickeya species
          (syn. Erwinia chrysanthemi Burkholder et al. 1953) 
          (syn. Erwinia herbicola (Löhnis 1911) Dye 1964)
Pantoea agglomerans (Ewing and Fife 1972) Gavini et al. 1989

FUNGI

Acrocalymma root and crown rot
Acrocalymma medicaginis Alcorn & J. A. G. Irwin
Massarina walkeri Shoemaker, C. E. Babc. & J. A. G. Irwin
Anthracnose
Colletotrichum trifolii Bain
Colletotrichum destructivum O’Gara
          (syn. Colletotrichum dematium f. sp. truncatum (Schwein.) Arx)
Colletotrichum gloeosporioides (Penz.) Penz. & Sacc.
Colletotrichum truncatum (Schwein.) Andrus & W. D. Moore
Blackpatch
Rhizoctonia leguminicola Gough & E. S. Elliott
Blossom blight (crown rot and stem rot)
Botrytis cinerea Pers.:Fr
Sclerotinia sclerotiorum (Lib.) de Bary
Brown root rot
Phoma sclerotioides Preuss ex Sacc.
          (syn. Plenodomus meliloti Dearn. & Sanford)
Charcoal rot
Macrophomina phaseolina (Tassi) Goid.
Common leaf spot
Pseudopeziza medicaginis (Lib.) Sacc.
Corky root rot
Xylaria sp.
Crown and root rot complex
Fusarium oxysporum Schltdl.
Fusarium solani (Mart.) Sacc.
Crown wart
Physoderma alfalfae (Pat. & Lagerh.) Karling
Cylindrocarpon root rot
Cylindrocarpon obtusiusculum (Sacc.) U. Braun
          (syn. Cylindrocarpon ehrenbergii Wollenw.)
Nectria ramulariae (Wollenw.) E. Müll
Cylindrocladium root and crown rot
Calonectria crotalariae (Loos) D. K. Bell & Sobers
Calonectria ilicicola Boedijn & Reitsma
Calonectria kyotensis Terash.
Cylindrocladium clavatum Hodges & L. C. May
Cylindrocladium parasiticum Crous, M. J. Wingf. & Alfenas
Cylindrocladium scoparium Morgan
Fusarium blight
Fusarium semitectum Berk. & Ravenel
Fusarium wilt
Fusarium oxysporum f. sp. medicaginis (Weimer) W. C. Snyder & H. N. Hansen
Lepto leaf spot
Leptosphaerulina briosiana (Pollacci) J. H. Graham & Luttr.
Mycoleptodiscus crown and root rot
Mycoleptodiscus terrestris (Gerd.) Ostaz.
          (syn. Leptodiscus terrestris Gerd.)
Phymatotrichopsis root rot
Phymatotrichopsis omnivora (Duggar) Hennebert
          (syn. Phymatotrichum omnivorum (Shear) Duggar)
Powdery mildew
Erysiphe pisi D. C.
Leveillula taurica (Lév.) Arn.
Rhizoctonia damping off (root canker, crown and bud rot, stem canker, and foliage blight)
Rhizoctonia solani. G. Kühn
Thanatephorus cucumeris (A. B. Frank) Donk
Rhizopus sprout rot
Rhizopus stolonifer (Ehrenb.) Vuill
Rust
Uromyces striatus J. Schröt.
Sclerotinia crown and stem rot
Sclerotinia trifoliorum Erikss. sensu Kohn
Sclerotinia sclerotiorum (Lib.) de Bary
Southern Sclerotium blight
Athelia rolfsii (Curzi) C. C. Tu & Kimbr.
Sclerotium rolfsii Sacc.
Spring black stem and leaf spot
Phoma medicaginis Malbr. & Roum.
Stagonospora leaf spot and root rot
Leptosphaeria weimeri Shoemaker, C. E. Babc. & J. A. G. Irwin
          (syn. Leptosphaeria pratensis Sacc. & Briard)
Stagonospora meliloti (Lasch) Petr.
Stemphylium leaf spot
Stemphylium botryosum Wallr.
Stemphylium vesicarium (Wallr.) E. Simmons
Summer black stem and leaf spot
Cercospora medicaginis Ellis & Everh.
Verticillium wilt
Verticillium alfalfae Inderb., H. W. Platt, R. M. Bostock, R. M. Davis & K. V. Subbarao
          (syn. Verticillium albo­atrum Reinke & Berthold)
Violet root rot
Helicobasidium brebissonii (Desm.) Donk
         (syn. Rhizoctonia crocorum (Pers.) DC.)
Winter crown rot
Coprinus psychromorbidus Redhead & Traquair
Yellow leaf blotch
Leptotrochila medicaginis (Fuckel) Schüepp
Sporonema phacidioides Desm.

NEMATODES (PARASITIC)

Alfalfa cyst nematode
Heterodera medicaginis Kirjanova & Krall
Barley root-knot nematode
Meloidogyne naasi Franklin
British root-knot nematode
Meloidogyne artiellia Franklin
Chrysanthemum foliar nematode
Aphelenchoides ritzemabosi (Schwarz) Steiner & Buhrer
Clover cyst nematode
Heterodera trifolii Goffart
Columbia root-knot nematode
Meloidogyne chitwoodi Golden, O’Bannon, Santo & Finley
Dagger nematode
Xiphinema americanum Cobb
False Columbia root-knot nematode
Meloidogyne fallax Karssen
Javanese root-knot nematode
Meloidogyne javanica (Treub) Chitwood
Lance nematode
Hoplolaimus sp.
Needle nematode
Longidorus africanus Merny
Northern root-knot nematode
Meloidogyne hapla Chitwood
Peanut root-knot nematode
Meloidogyne arenaria (Neal) Chitwood
Pin nematode
Paratylenchus sp.
Ring nematode
Criconemella sp.
Hemicriconemoides sp.
Root-lesion nematode
Pratylenchus coffeae (Zimmermann) Filipjev & Schuurmans Stekhoven
Pratylenchus crenatus Loof
Pratylenchus lentis Trocolli, DeLuca, Handoo & Di Vito
Pratylenchus neglectus (Rensch) Filipjev & Schuurmans Stekhoven
Pratylenchus penetrans (Cobb) Filipjev & Schuurmans Stekhoven
Pratylenchus pratensis (de Man) Filipjev
Pratylenchus thornei Sher & Allen
Pratylenchus vulnus Allen & Jensen
Southern root-knot nematode
Meloidogyne incognita (Kofoid & White) Chitwood
Spiral nematode
Helicotylenchus spp.
Rotylenchus sp.
Stem nematode
Ditylenchus dipsaci (Kühn) Filipjev
Stubby-root nematode
Paratrichodorus sp.
Trichodorus sp.
Stunt nematode
Merlinius sp.
Telotylenchus sp.
Tylenchorhynchus sp.

OOMYCETES

Aphanomyces root rot
Aphanomyces euteiches Drechsler
Downy mildew
Peronospora trifoliorum de Bary
Peronospora viciae (Berk.) Casp.
Phytophthora root rot
Phytophthora medicaginis E. M. Hansen & D. P. Maxwell
          (syn. Phytophthora megasperma Drechsler f. sp. medicaginis T. L. Kuan & Erwin)
Pythium seed and root rot
Pythium acanthicum Drechsler
Pythium aphanidermatum (Edson) Fitzp.
Pythium debaryanum R. Hesse
Pythium dissotocum Drechsler
Pythium irregulare Buisman
Pythium myriotylum Drechsler
Pythium paroecandrum Drechsler
Pythium pulchrum Minden
Pythium rostratum E. J. Butler
Pythium splendens Hans Braun
Pythium sylvaticum W. A. Campb. & F. F. Hendrix
Pythium torulosum Coker & P. Patt.
Pythium ultimum Trow
Pythium vexans de Bary
Pythium violae Chesters & Hickman

PARASITIC FLOWERING PLANTS

Field dodder
Cuscuta pentagona Engelm.
Large-seed dodder
Cuscuta indecora Choisy
Small-seed dodder
Cuscuta approximata Bab.

VIRUSES

Alfalfa enation
Alfalfa enation virus (AEV)
Alfalfa mosaic
Alfalfa mosaic virus (AMV)
Bean leafroll
Bean leafroll virus (BLRV)
Lucerne transient streak
Lucerne transient streak virus (LTSV)
Pea streak
Pea streak virus (PeSV) )
Red clover vein mosaic
Red clover vein mosaic virus (RCVMV)