Insect herbivore saliva can stimulate anti-herbivore defenses in plants during feeding beyond mere wounding. In our research we are attempting to determine the effects of Helicoverpa zea (corn earworm) caterpillar saliva on wound inducible gene expression of Zea mays corn plants on a genomic scale. In our experiment caterpillars fed on maize plants with the ability to secrete labial saliva or without the ability to secrete labial saliva (due to surgery) for three days. The leaves were then harvested and analyzed for wound inducible gene expression by using maize cDNA microarrays. Additional measures of plant defenses have been measured with chemical and biological assays.