Olive trees are grown in many regions of Syria, especially in wet regions
where the olive knot disease (Pseudomonas savastanoi pv.savastanoi ) prevails
.Symptoms similar to those found on olive trees have been observed on myrtle
shrubs (Myrtus com
munis) growing naturally in some olive-grown regions. This
study aimed at identifying the pathogen isolated from myrtle plant, and testing
the pathogenicity of these isolates on olive trees. Morphological, biochemical
and serological tests of bacteria isolated from myrtle showed similarity to
those from olive and other hosts. Pathogenicity tests showed that the myrtle
isolates were pathogenic on both myrtle and olive trees. Myrtle could be
considered as a source of inoculum for the olive knot disease.