First report of Phacidiopycnis rot of pears caused by Potebniamyces pyri (anamorph Phacidiopycnis piri) in British Columbia.

摘要

Potebniamyces pyri (anamorph Phacidiopycnis piri) causes a postharvest disease known as Phacidiopycnis rot primarily in stored winter pears and canker and twig dieback of apple and pear trees. Although Phacidiopycnis rot is known to occur in the bordering state of Washington, USA, it has not been reported in British Columbia (BC), Canada. Information was needed to determine if the disease occurred in BC and if it was as serious a problem on 'd'Anjou' winter pears as reported in Washington State. Surveys of stored BC pears, primarily 'd'Anjou', conducted in 2006 and 2007 showed that 39 and 26.5% of the culled fruit, respectively, were infected by P. pyri. The only other pathogen to cause similar amounts of decay was Botrytis cinerea. In order to confirm identification of this pathogen, single spore isolates were obtained from infected fruit and DNA was extracted from these isolates. Based on symptoms, colony and spore characteristics, and sequence analysis of both the ITS and beta -tubulin regions, the BC isolates were shown to be the same fungal species as the Washington State isolates previously identified as P. pyri. Furthermore, the isolates were shown to be as pathogenic on 'd'Anjou' pear fruit as were Washington State isolates. Field studies from established pear orchards showed that the fungus infected 'd'Anjou' pear trees in BC orchards causing cankers and branch dieback. Some possible methods of controlling this pathogen are discussed.