Definition:
Ilar virus of Vaccinium growing in the Pacific Northwestern North America. The virus is transmitted by pollen or seed and can be detected by ELISA/RT-PCR. Presence of the virus causes flower and fruit drop. Infection occurs during bloom and the virus moves into other parts of the plant in an uneven but steady manner and may take several years to become fully systemic in mature bushes. In the year after infection, emerging flower and leaf tissues die rapidly at full bloom followed by regrowth. Once symptoms have been exhibited in all parts of the plant, the plant remains asymptomatic in subsequent years. Infection in young plants of some cultivars can stunt the plant for the remainder of its life, however, more typically production is lost for one year.
Comment:
The descriptor is the number of years before the plant tests positive for Blueberry shock virus when growing in fields in the Pacific Northwestern North America (Oregon, Washington, or British Columbia). Lower values means that the plant succumbs to the virus faster; higher values means that the plant does not test positive for the virus for a longer time.
< 3 years = rapid to test positive
3 – 5 years = intermediate to test positive
5 – 10 years = slow to test positive
> 10 years = very slow to test positive.