One of the chief problems which Iowa farmers have in growing alfalfa is to find a satisfactory variety. Few alfalfa fields are worth leaving after the third year because wilt has thinned the stand so much. The Iowa Station, along with various others and the United States Department of Agriculture, has been trying to solve this problem by finding or developing varieties or strains which are wilt-resistant, winter-hardy and yield well.
Wilsie, C. P. and Hughes, H. D.
"Alfalfa That Lives,"
Farm Science Reporter: Vol. 2
, Article 6.
Available at: http://lib.dr.iastate.edu/farmsciencereporter/vol2/iss1/6