The green peach aphid (GPA), (Myzus persicae [Sulzer]) (Homoptera: Aphididae), is a phloem feeder that can utilize a variety of plant species, including stone fruits, ornamental shrubs and vegetables as host plants. Aphids like the GPA utilize their incredibly slender stylets to penetrate in between cells and consume copious amounts of photoassimilates from the phloem. The GPA can also act as a vector for >50 economically important plant viruses. Very little knowledge is available on plant response to aphids and on how aphids suppress or evade plant defense responses. We have utilized a model system consisting of Arabidopsis and GPA, which offers the combined power of genetics and genomic tools, to characterize the response of the plant host to GPA. In addition, we are adapting electrophysiological tools to understand GPA behavior on the wild type and defense compromised mutant plants. The Electrical Penetration Graph (EPG) technique is being standardized to monitor the feeding behavior of GPA on wild type and mutant Arabidopsis plants. The EPG technique enables us to monitor and quantify the different waveforms during the events of stylet penetration, ingestion, salivation and cell puncturing. Comparison of these recordings with the wild type and the mutant Arabidopsis plants will help us identify specific details contributing to aphid resistance/susceptibility. We anticipate that a better understanding of aphid behavior on the host plant will complement our genetic studies on plant defense against aphids in Arabidopsis, and thus uncover new targets for enhancing aphid resistance in crops.