We have previously demonstrated that infection with the R.
padi virus (RhPV) is common in Swedish populations of R. padi
(Ban et al., 2007). Aphids with this virus infection have a shorter
life span and lower population growth (D’Arcy et al., 1981). It
was thus of interest to investigate whether the effect of thiamine
treatments of barley versus R. padi would be different, depending
on the health status of aphids.