OLS is a bacterial disease caused by Xylella fastidiosa. Since then, OLS has been found across the southern United States and was recently reported in Louisiana.

fastidiosa grape and pear strains of Taiwan may have evolved independently from each other. Oleander leaf scorch (OLS) is a deadly disease of oleander that was first reported in California in the early 1990s. fastidiosa grape strains but not to the pear strains of Taiwan, suggesting that the X. Results showed that the PD strains of Taiwan were closely related to the American X. fastidiosa strains from different hosts and different geographical areas. Tough, waterwise and carefree oleanders all around the county are falling victim to an incurable bacterial disease. However, if an oleander is drought-stressed, the leaves begin turning yellow at the middle and then spread outward. woody plants that are reported hosts of X. Symptoms include drooping and yellowing leaves, which are also symptoms of drought stress or nutrient deficiencies. Bacterial leaf scorch is an important and often lethal disease of many. Phylogenetic analyses were performed by comparing the 16S rRNA gene and 16S-23S rRNA internal transcribed spacer region (16S-23S ITS) of 12 PD strains from Taiwan with the sequences of 13 X. Oleander leaf scorch is caused by the bacterial pathogen Xylella fastidiosa. This confirmed PD of grapevines is also the first report from the Asian Continent. During the spring of 1998, mature oleanders (Nerium oleander L.), pruned to form a 2-m-high hedge along an interstate highway in Orlando, FL, were observed. The inoculated plants developed typical leaf scorching symptoms, and similar disease severity developed in the three cultivars from which the bacterium was readily re-isolated, proving that the leaf scorch of grapevines in Taiwan is caused by the fastidious X. Koch’s postulates were fulfilled by artificially inoculating two purified PD bacteria to grape cultivars Kyoho, Honey Red and Golden Muscat. Bacterial leaf scorch caused by Xylella fastidiosa has been reported on oleander in California (3) and Florida (4). Xylella fastidiosa in oleander, almond and olive trees exhibiting leaf scorch. Diseased tissues were collected from fields for subsequent isolation and characterization of the causal agent of the disease (Xylella fastidiosa). PCR assays on extracts from leaf veins and petioles of diseased trees gave. It causes serious diseases in grapevines (Pierces disease), almonds (Almond leaf scorch), alfalfas (Alfalfa dwarf), and oleanders (Oleander leaf scorch) in.

Disease severity in vineyards varied, and all investigated grape cultivars were affected. Characteristic symptoms of Pierce’s disease (PD) in grapevines (Vitis vinifera L.) were observed in 2002 in the major grape production fields of central Taiwan.