Insect herbivory stimulates multiple plant responses that can set into motion plant stress and defense responses that can be both adaptive and counter adaptive to the plant. This presentation reports on the affects of Helicoverpa zea (corn earworm) caterpillar labial salivary gland enzymes on the wound-inducible gene expression of Lycopersicon esculentum (tomato) using tomato cDNA microarrays. Mechanically damaged tomato plants were treated with either H. zea caterpillar salivary gland extract, or autoclaved salivary gland extract and compared to a non-wounded control group to look at the differences in gene expression. Many of the known and important tomato plant defense genes such as protease inhibitors and polyphenol oxidase were not altered by labial salivary gland extract, but were stimulated by wounding; however arginase was stimulated by labial salivary gland extract. In addition, dehydrin and some heat shock proteins appear to be stimulated by labial salivary gland extract. This provides evidence that in general labial salivary gland enzymes may only moderately alter plant defense genes in tomato plants, and provides a framework for further analysis.