October 8, 2020
Here is an overview of common alfalfa diseases.
| Damping off | Root Rot | Crown Rot | Stem Rot | Leaf spots | |
| Pythium spp. | x | x | |||
| Phytophthora root rot (Phytophthora megasperma) | x | x | |||
| Fusarium wilt (Fusarium oxysporum f. sp. medicaginis) | x | x | |||
| Mycoleptodiscus crown and root rot (Mycoleptodiscus terrestris) | x | x | x | ||
| Rhizoctonia solani | x | x | x | ||
| Aphanomyces Root Rot (Aphanomyces euteiches) | x | ||||
| Bacterial wilt (Clavibacter michiganense ssp. insidiosus) | x | ||||
| Verticillium wilt (Verticillium albo-atrum) | x | x | |||
| Anthracnose (Collectotrichum trifolii) | x | x | |||
| Spring black stem and leaf spot (Phoma medicaginis) | x | x | x | ||
| Sclerotinia crown and stem rot (Sclerotinia trifoliorum, Sclerotinia sclerotiorum) | x | x | x | ||
| Summer black stem and leaf spot (Cercospora medicaginis) | x | x | |||
| Downy mildew (Peronospora trifoliorum) | x | x | |||
| Leptosphaerulina leaf spot (Leptosphaerulina briosiana) | x | ||||
| Yellow Leaf Blotch (Leptotrochila medicaginis) | x | ||||
| Common leaf spot (Pseudopeziza medicaginis) | x | ||||
| Stemphylium leaf spot (Stemphylium botryosum) | x | ||||
| Rust (Uromyces striatus medicaginis) | x | ||||
| Bacterial Leaf Spot (Xanthomonas campestris pv. Alfalfa) | x |
Verticillium Wilt (Verticillium albo-atrum)
Photo courtesy of William M. Brown Jr., Bugwood.org.
Anthracnose (Collectotrichum trifolii)
Photo courtesy of Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org.
Spring Black Stem and Leaf Spot (Phoma medicaginis)
Photo courtesy of University of Georgia Plant Pathology, University of Georgia, Bugwood.org.
Sclerotinia Crown and Stem Rot (Sclerotinia trifoliorum, Sclerotinia sclerotiorum)
Photo courtesy of Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org.
Downy Mildew (Peronospora trifoliorum)
Photo courtesy of G.J. Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org.
Common Leaf Spot (Pseudopeziza medicaginis)
Photo courtesy of Erik Stromberg, Virginia Polytechnic Institute and State University, Bugwood.org.
Stemphylium Leaf Spot (Stemphylium botryosum)
Photo courtesy of G.J. Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org.
OTHER DISEASES
Alfalfa Mosaic Virus (AMV) (Virus)
Photo courtesy of Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org.
Alfalfa Stem Nematode (Ditylenchus dipsaci) (Nematode)
Photo courtesy of Howard F. Schwartz, Colorado State University, Bugwood.org.
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