See:
Alfalfa (Medicago sativa) - Spring Black Stem and Leaf Spot (Black Stem)
Chemical control
- Meteor (Group 2) at 1.5 to 2 pints/A for seed crops only in Oregon only. No portion of treated seed crop may be used or distributed for food or feed. 24-hr reentry.
- Quadris Flowable (Group 11) at 6 to 15.5 fl oz/A applied prior to disease development. Use of an adjuvant is recommended. Do not apply within 14 days of harvest. 4-hr reentry.