Beware of grapevine yellows Bois noir, which has had a crippling
effect in European vineards, has shown up in British Columbia,
Canada. Wine grapes infected by Flavescence dorÃ©e, showing
brown, shrivelled fruits. The discovery of the disease Bois noir
in a South Okanagan vineyard late in 2006 was a wake-up call for
British Columbia grape growers of the need for vigilance against
a host of new diseases. During the B.C. Wine Institute's annual
viticulture conference in Penticton last summer, Dr. Chrystel
Olivier of Agriculture and Agri-Food Canada's Saskatoon Research
Centre told growers that Bois noir and other diseases known
generally as "grapevine yellows" could give them the blues if
they become established in the region. Vineyards around the
world have reported grapevine yellows, caused by microscopic
pathogens similar to bacteria known as phytoplasma. First
identified in 1967, phytoplasma are parasites of plant phloem
tissue and insects that serve as carriers of the disease.
Affected vines grow more slow