ASSOCIATION OF A BACILLUS SPECIES WITH LEAF AND TWIG DIEBACK OF ASIAN PEAR PYRUS PYRIFOLIA IN CHINA
B. Li, W. Qiu, Q.M. Tan, T. Su, Y. Fang, G.L. Xie
Leaf and twig dieback of Asian pear (Pyrus pyrifolia) was observed since 2006 in two orchards in Zhejiang Province (China). A gram positive bacterium was frequently isolated alone or in combination with Pseudomonas syringae pv. syringae from naturally infected twigs of field-grown pears. Inoculation of twigs with this bacterium resulted in the death of leaves and petioles as well as in twig dieback. The bacterium was identified as a Bacillus species (possibly Bacillus pumilus) by a polyphasic approach, including physiological and biochemical properties, carbon source utilization profile, fatty acid methyl esters and analysis of 16S rRNA gene sequence. This is the first report of the possible involvement of B. pumilus in leaf and twig dieback of Asian pear in China.