Effects of Leaf and Stem Diseases on Yield and Quality of Alfalfa Forage
- W. G. Willis,
- W. L. Stuteville and
- E. L. Sorensen
Field plots of alfalfa, Medicago sativa L., sprayed weekly with Dithane M-45 during the 1965 growing season to control leaf and stem diseases yielded 2.8 MT/ha (18%) more hay than did unsprayed plots (Average of four varieties in four cuttings). Disease control increased carotene content 21% (third cutting) and decreased stem defoliation 18%. Increases in annual forage yields in MT/ha, for sprayed over unsprayed plots, respectively, were ‘Cody’ 1.57 (8.8%), ‘Lahontan’ 3.47 (21.1%), ‘Ranger’ 3.11 (19.4%), and ‘Vernal’ 3.11 (26.9%).
Phoma medicaginis and Leptosphaerulina briosiana were the major pathogens in the first and second cuttings. Their control increased yields of Cody 4%, Lahontan 14%, Ranger 19%, and Vernal 19% for the first two cuttings combined. Cercospora zebrina was the principal pathogen in the third and fourth cuttings. Control of C. zebrina increased yields of Cody 16%, Ranger 29%, Lahontan 30%, and Vernal 38% for the third and fourth cuttings combined. Corresponding increases in carotene content for the third cutting were 17, 20, 45, and 10%, respectively.
Defoliation was reduced by spray treatments. Protein percentage was not affected.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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