ASH                        YELLOWS Ash yellows is caused by a microbe called a phytoplasma, which causes a general decline of the tree.

Symptoms: Tree decline with loss of dominance. Leaves are stunted and chlorotic.       Photo by Cornell University, Department of Plant Pathology

Symptoms: Witches brooming near the base of the trunk. Photo by Cornell University, Department of Plant Pathology

General Information

Causal organism:	Phytoplasma
Over wintering:	In plant material
Months of infection:	Unknown
Method of dispersal:	Unknown, possibly insect
Infection point:	Unknown

Control Measures

Control:	Increase the vigor of the tree through proper watering, fertilizing, and mulching. Prune dead or dying branches. Remove severely infected trees.
Labelled fungicides:	None
Comments:	Ash yellows is often associated with other environmental factors or fungal diseases, resulting in a general decline.

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Plant Disease Diagnostics
University of Minnesota, Yard and Garden Clinic
Developed (1999) and maintained by
Chad J. Behrendt, Ph.D. and Crystal M. Floyd

For plant disease questions contact the Yard and Garden Line Content Last Updated 09/07/00 View University of Minnesota Disclaimer