A new Alternaria species identified on Ya Li pears (Pyrus bretschneideri)
In the early 1990s, China began to export fruits of Ya Li pears (Pyrus bretschneideri) from Hebei province to several countries including Australia, Canada, New Zealand and USA. In 2001/2002, 27 consignments of Ya Li pear fruits showing symptoms of an Alternaria disease were rejected at different points of entry in USA. Interceptions of similarly decayed Ya Li pear fruits were noted in 2001 in Australia, New Zealand and United Kingdom. In Canada, Ya Li pear fruits with symptoms of Alternaria sp. had been reported as early as 1993. In March 2002, imports into the USA were suspended essentially because of the detection of the Fusicladium anamorph of Venturia nashicola (EU Annexes) but also because of the repeated interceptions of Alternaria sp. Affected fruits showed dark lesions (chocolate brown) with pale reddish brown margins, often associated with stem lesions. Studies were done to identify the causal agent. Morphological, pathological and genetic characteristics of the Alternaria isolates clearly differentiate them from Alternaria alternata, A. gaisen and other species known to occur commonly on pome fruits. Although the disease might be caused by several species of Alternaria, one of these taxa could be described as a new and distinct species called Alternaria yaliinficiens sp. nov.
Roberts RG (2005) Alternaria yaliinficiens sp. nov. on Ya Li pear fruit: from interception to identification. Plant Disease 89(2), 134-145.