Abstract
Date palm, (Phoenix dactylifera L.) is a valuable fruit crop in the Middle East including Saudi Arabia and Jordan. The phytoplasma (Alwijam) disease, caused by Candidtus phytoplasma, is considered one of the most important diseases that affect the sustainability of date palm. One thousand and fifty seven date palm samples were collected from different locations in Saudi Arabia and Jordan and tested for Alwijam using nested polymerase chain reaction (nPCR) with sets of primers P 1/P7 and R16F2n/R16R2. The percentage of occurrence of phytoplasma in the collected samples were 11.3% in Saudi Arabia and 8.4% in Jordan. Nucleotide sequences for 16S rRNA gene of obtained isolates were carried out and virtual Restriction Fragment Length Polymorphism RFLP patterns analysis were used to study the diversity of the pathogen that causing Alwijam disease in both countries. Phytoplasma groups 16SrI, 16SrII and 16SrV reported to be associated with Alwijam disease on date palm in both countries. This study has demonstrated that Alwijam disease identified for first time in Jordan and the group 16SrV reported for first time associated with Alwijam disease.