USDA Forest Service
 

Forest Health Protection, Southern Region

 

USDA Forest Service
Forest Health Protection
Region 8
1720 Peachtree Road, NW
Room 816 N
Atlanta, GA 30309

Phone: (404) 347-7478
Fax: (404) 347-1880

United States Department of Agriculture Forest Service.

USDA Link Forest Service Link

 

ELM PHLOEM NECROSIS,

caused by Mycoplasma

 

Importance. - This disease kills more elms than Dutch elm disease in many urban areas. It is prevalent in the eastern half of the nation. The disease is common on winged and American elms, but attacks all elms.

Identifying the Cause. - Mycoplasma, which are microscopic plants, cannot be field identified. Consult a specialist.

Identifying the Injury. - Symptoms appear initially on one branch or a small portion of the crown. Leaves wilt, become chlorotic, and their margins curl upwards. Defoliation follows, and the crown appears bushy. Defoliation and death can occur in a few weeks. Some of the brown, wilted leaves persist, separating these symptoms from Dutch elm disease. This disease is identified by the butterscotch discoloration of the inner bark of the host tree. A wintergreen odor can sometimes be smelled after placing the affected bark in a vial or plastic bag.

 

 

Butterscotch discoloration of inner bark

Butterscotch discoloration of inner bark.

 

 

Biology. - Leafhoppers that have previously fed on infected elms transmit the mycoplasma to healthy elms.

Control. - Removal of dying or dead trees will reduce the spread of this disease by reducing the source of the mycoplasma.

 

USDA Forest Service - Forest Health Protection, Southern Region
Last Modified: Monday, 16 December 2013 at 14:18:29 CST


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