Fig. 2. Time course of population growth of aphids (R. padi) on barley plants (cv.
Lina) treated with thiamine. Seeds were soaked in 150 lMof thiamine (B1) or water
before germination. Twenty aphids were added to 7 days old plants. Each following
day during 1 week, the infestation was terminated and the numbers of aphids
counted on some of the plants. The results are means (±s.e., not visible) of five
replicates.