Extension Soil Specialist, University of California-Davis Alfalfa yellows was first studied in the 1950's in Central Washington as a new problem. The study ended in the mid-sixties as researchers found no disease organism or plant nutrient deficiency associated with alfalfa yellows and no information was published from these early studies.
Leaves are light green to yellow and distorted, especially terminal leaves.
In severe cases, stunted plants may be only several inches tall. Alfalfa yellows symptoms may be confused with symptoms of other growth problems, such as bacterial wilt. The alfalfa yellows have been observed in all cuttings except the first. Each site was approximately 20 feet X 20 feet. Soil and plant samples were taken from each site on the date when alfalfa growth was at least 12-15 inches tall.