The source plant for phytoplasmas in the Israeli vineyards is still a mystery

The fact that phytoplasma could not be detected in Vitex agnus-castus which is the preferred host of the insect vector, suggested that other plant species are involved. Israeli vineyards and surroundings were surveyed. Samples from grapevines, wild and cultivated species were analysed. To confirm the presence of phytoplasma, DNA was extracted and amplified using general phytoplasma ribosomal primers and specific tub primers. Phytoplasma tuf-type was identified by PCR/RFLP analyses. The results show that “stolbur” phytoplasma tuf-type b is the only type that was detected in symptomatic grapevines but it was not detected in any other plant species that was sampled. In V. agnus-castus, Convolvulus, Urtica and Crepis, considered as potential host plants, peanut witches’ broom (16SrII) or pigeon pea witches’ broom (16SrIX) related phytoplasmas were detected in 2.8–23% of the samples. Consequently, the source plant for “stolbur” phytoplasma in vineyards remains unknown.