First report of bacterial gall on Loropetalum chinense caused by Pseudomonas savastanoi in the United States.
Bacterial gall symptoms were observed on Loropetalum chinense in two separate commercial nurseries in South Alabama during the spring of 2012. Limb dieback and plant death was first reported by the growers. Plants with dieback symptoms had galling and irregular dark callus formation on the lower stem and lower branches. Galls were small, 0.2 to 1 cm, inconspicuous, and in some cases girdled the stem causing breakage of the main stem. In both locations, 30 to 40% of the crop was affected. Similar symptoms have been observed on L. chinense in nursery and landscape plantings in central Alabama, North Carolina, and Georgia in previous years. Bacterial colonies were isolated from four plants representing two different locations. Based on morphological, biochemical, molecular (rDNA sequence analysis) and pathogenicity tests, the isolates were identified as P. savastanoi. This is thought to be the first report of bacterial gall of L. chinense caused by P. savastanoi in the United States.