The intimate relationship between an aphid and its host is mediated by the composition of the secreted saliva. In the present study, aphid heads were sampled and transcript profiling conducted after aphids were fed on their preference host and transferred to a variety of preference and nonpreference hosts. It was found that the virulent Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) biotype SAM was able to selectively up-regulate more transcripts when confronted with feeding on a variety of hosts, than was the case with the less virulent D. noxia biotype SA1, suggesting increased genomic regulation when coping with a stressful environment. Collectively, the observed transcriptomic changes are supported by previous findings that host changes induce significant changes in the proteome of phytophagous hemipterans, unlike in many other entomophagous generalist species. The current data suggest that highly specialized hemipterans may be able to counter plant defenses with inducible salivary transcripts with resulting protein biosynthesis, as demonstrated here.