Seasonal Variations in Detection and Transmission of Pear Decline Phytoplasma

The seasonal variation in the detection of the pear decline phytoplasma was followed in diseased pear trees pertaining to the cultivars Limonera , Magallo´ n and Monsallard . Wood and ⁄ or leaf samples were obtained every two weeks at five different above-ground levels and analyzed using nested-PCR (Polymerase Chain Reaction). The results revealed that it was possible to detect the pathogen during the dormant season in the aerial parts of the diseased trees examined under the environmental conditions used in this study. Moreover, graft transmission experiments showed that the phytoplasmas can be propagated through grafting with phytoplasma-infected dormant buds collected in winter. The results are discussed in terms of their implication for pear cultivation and propagation