Seasonal Occurrence and Abundance of Sharpshooter Leafhoppers in Alabama Orchards and Vineyards

Abstract

Although the bacterium Xylella fastidiosa (Xf) has been confirmed to cause economic losses to numerous fruit crop species in the southeastern U.S. since 1933, no science-based information is available on the occurrence of infection in economic fruit crops grown in Alabama, as well as the presence of effective Xf vectors in the state. An investigation to identify the sharpshooter (Hemiptera: Cicadellidae) fauna and to determine their occurrence in selected orchards and vineyards was conducted in Alabama during 2008–2009. Leafhoppers were trapped in three different geographic locations: in the Gulf Coast, Central, and North Alabama. Seven species of sharpshooters were identified, including: Homalodisca vitripennis (Germar), H. insolita (Walker), Oncometopia orbona (Fabricius), Paraulacizes irrorata (Fabricius), Graphocephala coccinea (Forster), Graphocephala versuta (Say), and Draeculacephala spp. H. vitripennis and G. versuta were the most prevalent species in Alabama orchards and vineyards; however, their proportion varied by location. H. vitripennis was the most abundant species trapped in the Gulf Coast area, whereas G. versuta was the most prevalent sharpshooter species in Central and North Alabama. The results are discussed in relation to the likelihood and efficiency of these species as Xf vectors in Alabama.