There is a high possibility that pollen imported from New Zealand was a source of infection for the nation’s first case of kiwifruit bacterial canker disease Psa3 confirmed in Ehime Prefecture in May, the prefecture said in its report released on Thursday, July 24.
The prefecture said the same type of imported pollen was used by all of the 17 farms where the primary infection presumably took place. Fruit Tree Research Center in Ehime, the nation’s largest kiwifruit production area, said high concentration of live Psa3 bacteria was detected from three samples of imported pollen provided by the farms.
To prevent the disease from spreading, local governments and agricultural co-operatives cut all the trees in the orchards where the outbreak occurred. But since New Zealand manages to control the disease by early detection and partial removal of branches, Ehime Prefecture set a new rule allowing partial cutting of infected trees or branches for orchards with minor damage, such as spots found only on a couple of leaves.
“We encourage growers to use pollens whose safety is confirmed and leave notes (of the usage history) from now on,” Ehime Gov. Tokihiro Nakamura said in a press conference.
After confirming infection and issuing a special warning on May 2, the prefecture set up an investigation team in May 19 to identify the route of infection by conducting surveys on farms in Ehime and abroad.
Out of 44 farms surveyed, the investigation team assumed from the timing of infection that 17 farms were primarily infected and 26 other farms were infected due to secondary transmissions. The team could not clarify the route of infection for the remaining one farm.
(July 25, 2014)