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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)