ARS | Publication request: Alfalfa diseases 101: diagnosing common and emerging disease problems

Submitted to: Forage Focus
Publication Type: Trade Journal
Publication Acceptance Date: July 18, 2011
Publication Date: December 1, 2011
Citation: Samac, D.A. 2011. Alfalfa diseases 101: diagnosing common and emerging disease problems. Forage Focus. August 2011. p. 4-5.

Technical Abstract: More than 50 pathogens have been identified that cause significant damage to alfalfa and prevent it from reaching its full potential for producing high yields of quality forage. There has been excellent progress by plant breeders and plant pathologists in developing cultivars with multiple disease and pest resistance adapted to each region of the country. Yet, despite these advances, alfalfa yields have not increased appreciably. From a plant pathologist's perspective, new disease-causing organisms or new races of previously described pathogens may be playing a role in limiting yields. Also, pathogens previously considered to cause minor damage may be becoming more problematic, particularly with shifting agricultural practices and changing environmental patterns. Alfalfa producers, industry representatives, agricultural consultants, and extension personnel are on the "front lines" for identifying emerging alfalfa disease problems. This article describes the best practices for reducing the potential for disease to occur and how to diagnose disease problems. Three common foliar diseases prevalent during late summer and fall, common leaf spot, Lepto leaf spot, and alfalfa rust, as well as several emerging disease problems are described.