Alfalfa Seed Selection
The new free publication, “2023 Winter Survival, Fall Dormancy & Pest Resistance Ratings for Alfalfa Varieties” is now available online through the Alfalfa and Forage Alliance. For Nebraska producers, the two most serious alfalfa diseases are anthracnose and Phytophthora root rot. Both disease symptoms are most devastating on susceptible alfalfa varieties. Therefore, proper seed selection will be the first disease management line of defense. Select improved seed varieties with at least a moderate to high resistance to anthracnose and Phytophthora root rot to effectively prevent yield and stand losses. Also, consult your seed representative to get the best protection for your alfalfa fields.
Anthracnose can appear anytime of the year on any age of alfalfa stand. Affecting stems and crowns, this disease can move rapidly and lower forage production in as little as one to two growing seasons. In some cases, disease stress can reduce alfalfa’s ability to withstand cold temperatures resulting in winter or spring kill.
Phytophthora root rot is the most common root rot affecting all stages of alfalfa causing seedling death. This pathogen can cause seedling damping off in new stands followed by plant death in wet conditions in as little as a few days. In established stands, Phytophthora root rot causes taproot lesions resulting in up to a 50% yield loss and progressive decline over time and potential kill.
More alfalfa disease management information is available on CropWatch. Also, positive alfalfa disease identification can be confirmed by submitting samples to our UNL Extension Plant and Pest Diagnostic Clinic.