The severe impact of Pierce’s Disease upon the U.S. grape industry has generated the need to rapidly understand the epidemiology of this disease. The primary insect vector is a leafhopper, the glassy-winged sharpshooter, GWSS. Our objectives are to develop environmentally friendly, sound management programs to reduce the spread of Pierce’s Disease. Through the use of cDNA libraries of GWSS midguts we have identified digestive enzymes that are expressed during adult feeding. By elucidating GWSS digestion we will gain insights into host plant utilization and potentially identify new genetic targets for use in the management of this serious agricultural vector of Pierce’s Disease.