Phytoplasmas that are associated with fruit crops, vegetables, cereal and oilseed crops, trees, ornamental, and weeds are increasing at an alarming rate in the Middle East. Up to now, fourteen 16Sr groups of phytoplasma have been identified in association with more than 164 plant species in this region. Peanut witches’ broom phytoplasma strains (16SrII) are the prevalent group, especially in the south of Iran and Gulf states, and have been found to be associated with 81 host plant species. In addition, phytoplasmas belonging to the 16SrVI, 16SrIX, and 16SrXII groups have been frequently reported from a wide range of crops. On the other hand, phytoplasmas belonging to 16SrIV, 16SrV, 16SrX, 16SrXI, 16SrXIV, and 16SrXXIX groups have limited geographical distribution and host range. Twenty-two insect vectors have been reported as putative phytoplasma vectors in the Middle East, of which Orosius albicinctus can transmit diverse phytoplasma strains. Almond witches’ broom, tomato big bud, lime witches’ broom, and alfalfa witches’ broom are known as the most destructive diseases. The review summarizes phytoplasma diseases in the Middle East, with specific emphasis on the occurrence, host range, and transmission of the most common phytoplasma groups.

This study was carried out to investigate the effects of cold acclimation, cooling rate and heat stress on supercooling capacity and cold hardiness of the potato tuber moth (PTM), Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae). Supercooling points (SCP) of first and last instar larvae, prepupae and pupae were -21.8, -16.9, -18.9 and -18.0°C, respectively. Cold acclimation (1-week at 0 and 5°C) did not affect SCPs of acclimated last instar larvae, prepupae and pupae. LT₅₀s (lower lethal temperature for 50% mortality) for first and last instar larvae, prepupae and pupae were -15.5, -12.4, -17.9 and -16.0°C, respectively. Cold acclimation resulted in a significant decrease in mortality of all developmental stages. In addition, the mortality rates of the different developmental stages decreased with decrease in cooling rate. In addition, heat hardening (kept at 40°C for 2 h) significantly reduced mortality of all developmental stages exposed to LT₅₀ conditions, suggesting that heat hardening also affects cold tolerance. Results indicate that none of the stages could tolerate subzero temperatures below their SCPs, indicating that this species might be a chill tolerant insect. These adaptive responses may allow PTM to enhance its cold tolerance and colonize cold regions.

Artemisia sieberi showing symptoms resembling those caused by phytoplasma were observed in Geno Mountain, Hormozgan Province, Iran, and were examined for phytoplasma presence by PCR assays. In addition, the essential oils hydrodistilled from the aerial parts of phytoplasma-infected and healthy plants have been analyzed and compared by GC and GC/MS. Phylogenetic and virtual RFLP analysis of the 16S rRNA gene sequences revealed that the phytoplasma associated with A. sieberi witches' broom (AsWB) was a strain of 'Candidatus Phytoplasma aurantifolia'. The presence of the disease, however, induced a further enrichment (from 4.9 to 45.2%, a relative increase of 90%) of the entire monoterpene class as compared to the abundance in healthy samples. Conversely, a matching decrease in monoterpenoid (from 48.7 to 2%, a relative decrease of 90.2%) was observed in the infected plants. Besides the first report of phytoplasma infection of A. sieberi, the changes of its essential oils are reported.