Grapevine Yellows (GY) is a destructive phytoplasma disease of winegrapes that is more common in vines along vineyard edges adjacent to forests. Edge effects in the distribution of diseased vines suggest that GY is likely transmitted by phloem-feeding insects (leafhoppers, planthoppers and psyllids) moving into the vineyard from wild hosts in the forest or along forest edge. We are investigating the relative incidence and seasonal movement of candidate vector species in the vineyard and in adjacent forests using sweep nets sampling, transects of sticky traps and bidirectional malaise traps. Vector competence is initially determined by PCR assays of captured insects using phytoplasma specific primers. To date, our findings indicate that seasonal distribution of candidate vectors across the forest/vineyard interface is species specific, although many species were more abundant at the ecotone. The distribution of two leafhopper species, Scaphoideus titanus, a GY vector in Europe, and Jikradia olitorius could account for the higher incidence of disease observed at vineyard edges. Our overall goal is to determine how the structure of the landscape influences the incidence and abundance of potential GY vector species and, ultimately, how it might be manipulated to reduce their numbers.