This article is a list of diseases of alfalfa (Medicago sativa).
| Bacterial diseases | |
|---|---|
| Bacterial leaf spot | Xanthomonas campestris pv. alfalfae |
| Bacterial sprout rot | Erwinia chrysanthemi pv. chrysanthemi |
| Bacterial stem blight | Pseudomonas savastanoi pv. phaseolicola = P. medicaginis |
| Bacterial wilt | Clavibacter michiganensis subsp. insidiosus = Corynebacterium insidiosum |
| Crown gall | Agrobacterium tumefaciens |
| Crown and root rot complex | Pseudomonas viridiflava |
| Dwarf | Xylella fastidiosa |
| Fungal diseases | |
|---|---|
| Acrocalymma root and crown rot | Acrocalymma medicaginis Massarina walkeri [teleomorph] |
| Anthracnose | Colletotrichum trifolii |
| Aphanomyces root rot | Aphanomyces euteiches |
| Black patch | Rhizoctonia leguminicola |
| Black root rot | Thielaviopsis basicola Chalara elegans [synanamorph] |
| Blossom blight | Botrytis cinerea Botryotinia fuckeliana [teleomorph] Sclerotinia sclerotiorum |
| Brown root rot | Phoma sclerotioides Plenodomus meliloti |
| Crown and root rot complex | Fusarium acuminatum Gibberella acuminata [teleomorph] Fusarium avenaceum Gibberella avenacea [teleomorph] Fusarium equiseti Fusarium oxysporum Fusarium sambucinum Fusarium solani Nectria haematococca [teleomorph] Fusarium spp. Phoma medicaginis Pythium spp. Rhizoctonia solani Thanatephorus cucumeris [teleomorph] Thielaviopsis basicola Chalara elegans [synanamorph] |
| Charcoal rot | Macrophomina phaseolina |
| Common leaf spot | Pseudopeziza medicaginis |
| Corky root rot | Xylaria sp. |
| Crown wart | Physoderma alfalfae Urophlyctis alfalfae |
| Cylindrocarpon root rot | Cylindrocarpon magnusianum Cylindrocarpon ehrenbergii Nectria ramulariae [teleomorph] |
| Cylindrocladium root and crown rot | Cylindrocladium crotalariae Calonectria crotalariae [teleomorph] |
| Damping-off | Fusarium acuminatum Gibberella acuminata [teleomorph] Mycoleptodiscus terrestris Phytophthora medicaginis Phytophthora megasperma f.sp. medicaginis Pythium spp. Pythium debaryanum Pythium irregulare Pythium splendens Pythium ultimum Rhizoctonia solani Thanatephorus cucumeris [teleomorph] |
| Downy mildew | Peronospora trifoliorum |
| Fusarium wilt | Fusarium oxysporum f.sp. medicaginis |
| Lepto leaf spot | Leptosphaerulina trifolii |
| Marasmius root rot | Marasmius sp. |
| Mycoleptodiscus crown and root rot | Mycoleptodiscus terrestris |
| Myrothecium root rot | Myrothecium roridum Myrothecium verrucaria |
| Phymatotrichum root rot = cotton root rot = Texas root rot | Phymatotrichopsis omnivora Phymatotrichum omnivorum |
| Phytophthora root rot | Phytophthora medicaginis Phytophthora megasperma f.sp. medicaginis |
| Powdery mildew | Erysiphe pisi Leveillula taurica |
| Rhizoctonia root rot and stem blight | Rhizoctonia solani Thanatephorus cucumeris [teleomorph] |
| Rhizopus sprout rot | Rhizopus stolonifer |
| Rust | Uromyces striatus Uromyces medicaginis Uromyces oblongus Uromyces striatus var. medicaginis |
| Sclerotinia crown and stem rot | Sclerotinia trifoliorum Sclerotinia sclerotiorum |
| Southern blight | Sclerotium rolfsii Athelia rolfsii [teleomorph] |
| Spring black stem and leaf spot | Phoma medicaginis |
| Stagonospora leaf spot and root rot | Stagonospora meliloti Phoma meliloti [synanamorph] Leptosphaeria pratensis [teleomorph] |
| Stemphylium leaf spot | Pleospora spp. Stemphylium alfalfae Pleospora alfalfae[teleomorph] Stemphylium botryosum Pleospora tarda [teleomorph] Stemphylium globuliferum Stemphylium herbarum Pleospora herbarum [teleomorph] Stemphylium vesicarium species complex |
| Summer black stem and leaf spot | Cercospora medicaginis |
| Verticillium wilt | Verticillium albo-atrum Verticillium dahliae |
| Violet root rot | Helicobasidium brebissonii Rhizoctonia crocorum[anamorph] |
| Winter crown rot = Coprinus snow mold | Coprinus psychromorbidus |
| Yellow leaf blotch | Leptotrochila medicaginis Pyrenopeziza medicaginis Pseudopeziza jonesii Sporonema phacidioides [anamorph] |
| Nematodes, parasitic | |
|---|---|
| Bulb and stem nematode | Ditylenchus dipsaci |
| Chrysanthemum foliar nematode | Aphelenchoides ritzemabosi |
| Cyst nematode | Heterodera trifolii |
| Dagger nematode | Xiphinema americanum |
| Lesion nematode | Pratylenchus spp. Pratylenchus neglectus Pratylenchus penetrans |
| Needle nematode | Longidorus spp. |
| Pin nematode | Paratylenchus spp. Paratylenchus hamatus |
| Reniform nematode | |
| Root-knot nematode | Meloidogyne spp. Meloidogyne arenaria Meloidogyne chitwoodi Meloidogyne hapla Meloidogyne incognita Meloidogyne javanica |
| Spiral nematode | Helicotylenchus spp. |
| Stubby-root nematode | Paratrichodorus spp. |
| Stunt nematode | Tylenchorhynchus spp. |
| Viral diseases | |
|---|---|
| Alfalfa enation | genus Rhabdovirus, Alfalfa enation virus (AEV) |
| Bean leaf roll | genus Luteovirus, Bean leaf roll virus (BLRV) |
| Bean yellow mosaic | genus Potyvirus, Bean yellow mosaic virus (BYMV) |
| Cucumber mosaic | genus Cucumovirus, Cucumber mosaic virus (CMV) |
| Lucerne Australian latent | genus Nepovirus, Lucerne Australian latent virus (LALV) |
| Lucerne Australian symptomless | genus Comoviridae, Lucerne Australian symptomless virus (LASV) |
| Lucerne transient streak | genus Sobemovirus, Lucerne transient streak virus (LTSV) |
| Pea streak | genus Carlavirus, Pea streak virus (PSV) |
| Red clover vein mosaic | genus Carlavirus, Red clover vein mosaic virus (RCVMV) |
| Tobacco streak | genus Ilarvirus, Tobacco streak virus (TSV) |
| White clover mosaic | genus Potexvirus, White clover mosaic virus (WCMV) |
| Phytoplasmal and spiroplasmal diseases | |
|---|---|
| Aster yellows | Aster yellows phytoplasma |
| Witches'-broom | Phytoplasma |