RATES AND PATTERNS OF TOBACCO STREAK VIRUS SPREAD IN ‘BOYSEN’ AND IN RED RASPBERRY

During four years of measurement in an Oregon field plot the Rubus strain of tobacco streak virus (TSV-R) spread from infected to adjoining healthy ‘Boysen’ plants at an annual rate of about 7%. The distribution patterns of TSV-R in ‘Boysen’ rows were predominantly random.
The spread of TSV-R in red raspberry was also documented for the first time.
In four rows of ‘Willamette’ red raspberry adjoining the ‘Boysen’ plot and observed for five years, plants in the row next to ‘Boysen’ had an annual infection rate near 7%. A steep infection gradient (slope -9.0) that was not influenced by the presence or absence of flowers occured across the ‘Willamette’ plot.
Patterns of distribution of TSV-R within ‘Willamette’ rows were nearly all random during the measurement period. ‘Boysen’ appeared to be the primary source of TSV-R inoculum, with little secondary spread in the ‘Willamette’ plot.
Since TSV-R spread is known from earlier work to be strongly flower-associated in ‘Boysen’ but does not appear to be flower-associated in ‘Willamette’, two distinct modes of transmission should be anticipated for this virus in Rubus.
Separation of new, healthy red raspberry plantings by even a few blank rows from infected ‘Boysen’ or similar plantings should markedly reduce the spread of TSV-R into the red raspberries.

IV International Symposium on Small Fruit Virus Diseases

R.H. Converse

https://doi.org/10.17660/ActaHortic.1986.186.4