Effect of soaking barley seeds (cv. Lina) in 150 lM thiamine on life span, fecundity and intrinsic rate of population increase (rm) of uninfected and RhPV-infected R. padi aphids. The results are means (±s.e.) of fifteen replicates. Asterisks indicate significant differences between control (soaking in water) and treatment with Mann–Whitney-test (⁄P 6 0.05;
⁄⁄P 6 0.01; ⁄⁄⁄P 6 0.001).