How to Manage Pests

UC Pest Management Guidelines

Dry Beans

Alfalfa Mosaic (Yellow Dot)

Pathogen: Alfalfa mosaic virus (AMV)

(Reviewed 8/07, updated 8/07)

In this Guideline:


Symptoms of alfalfa mosaic in beans vary depending on the strain of the virus. Some strains cause only localized symptoms that may include necrotic spots on infected leaves. Other strains infect the entire plant and cause symptoms ranging from yellow dots to a striking yellow mottle, which may be accompanied by leaf and pod distortion and stunted plant growth.


Alfalfa mosaic virus has a wide host range and is transmitted from plant to plant by various aphids. Alfalfa is an important perennial host for alfalfa mosaic.


Alfalfa mosaic is a minor disease of beans in California and warrants no control measures. Growers should plant certified seed and may want to avoid planting bean fields adjacent to alfalfa fields.


[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Dry Beans
UC ANR Publication 3446


R. M. Davis, Plant Pathology, UC Davis
C. A. Frate, UC Cooperative Extension, Tulare County

Acknowledgment for contributions to Abiotic Disorders:
A. E. Hall, Botany and Plant Sciences, UC Riverside
Acknowledgment for contributions to Diseases/Abiotic Disorders:
S. R. Temple, Plant Sciences, UC Davis
Acknowledgment for contributions to Diseases (viruses):
R. L. Gilbertson, Plant Pathology, UC Davis

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