Occurrence of mycoplasma‐like organisms in diseased and non‐symptomatic alder trees (Alnus spp.)

Mycoplasma‐like organisms (MLOs) were detected in almost all examined trees of Alnus glutinosa and A. incana older than approximately 5 years. The minority of trees showed symptoms of decline while the others appeared healthy. MLOs were also found in A. glutinosa var. barbata, A. hirsuta, A. rubra, A. rugosa, A. subcordata, and A. tenuifolia.