Glucosinolates (GS) and their breakdown products are Crucifer-specific defensive secondary metabolites, which deter many generalist insect herbivores. Feeding by Myzus persicae (green peach aphid, a generalist herbivore) significantly induced GS in aphid-treated leaves of Arabidopsis land races Columbia-0 and Landsberg erecta. However, systemic induction of GS in untreated leaves was not observed. Two GS, 8-methylsulfinyloctyl-GS and 4-methoxyindol-3-ylmethyl-GS were consistently induced two to five days after aphid treatment. Application of salicylic acid (SA), a plant defense signaling molecule, is also known to induce those two GS. However, induction of GS by aphids in SA-deficient mutants was similar to wild type plants, suggesting that SA signaling pathways are not involved in the induction of GS by M. persicae feeding. Other possible pathways for aphid-mediated GS induction are being investigated.