Studies on pear decline in Taiwan
In 1994, typical symptoms of pear decline were observed in central Taiwan on Asian pears (Pyrus pyrifolia). Molecular studies showed that a phytoplasma was consistently associated with the disease but that it was different from ‘Candidatus Phytoplasma pyri’ (EPPO A2 List) which is associated with pear decline in North America and Europe. Molecular and phylogenetic studies suggested that the Taiwanese pear decline phytoplasma might represent a new subgroup (closely related to ‘Candidatus Phytoplasma prunorum’) within the apple proliferation group. In central Taiwan, two species of pear psyllids have been identified in pear orchards: Cacopsylla chinensis and C. qianli (Homoptera: Psyllidae). The Taiwanese pear decline phytoplasma could be detected in both insects, suggesting that these could be candidates for transmitting the disease in pear orchards. However, transmission studies are needed to verify this hypothesis.
Liu HL, Chen CC, Lin CP (2007) Detection and identification of the phytoplasma associated with pear decline in Taiwan. European Journal of Plant Pathology 117(3), 281-291.