Technical Abstract: Leafhoppers, (Hemiptera) are considered the second most important group of plant pathogen vectors. Three leafhopper species which transmit Xylella fastidiosa, a plant pathogen of fruit crops, were examined by comparison of the available expressed sequence tags, ~43,400 ESTs (Hunter datasets, National Centre Biotechnology Information). The plant-pathogenic bacterium, Xylella fastidiosa is the causal agent of Pierce’s disease of grapevine. Examination of gene expression across these leafhopper species, the glassy-winged sharpshooter, Homalodisca vitripennis, blue-green sharpshooter, Graphocephala atropunctata, and black-winged sharpshooter, Oncometopia nigricans, compared approximately 4,800 specific transcripts for each species, with most of these (~40-48%) being identified as house-keeping. These are predicted to be approximately one-fourth of the active genes of these leafhoppers, based on comparative analysis of genomes of other insects in the order Hemiptera. Study of transcripts specific to delta-9 desaturase enzymes which play a vital role in the internal metabolism and physiology of insects, with additional analyses demonstrated significant differences for species-specific targeting of these genes within leafhoppers. Strategies like RNA-interference should be able to design specific and effective management tools to reduce leafhopper abundance, and/or reduce transmission of plant pathogens.