Frankliniella fusca (Thysanoptera: Thripidae), The Vector of Tomato Spotted Wilt Orthotospovirus Infecting Peanut in the Southeastern United States

Abstract

The tobacco thrips, Frankliniella fusca Hinds, is a phytophagous pest and vector of orthotospoviruses in many crops around the world. F. fusca causes direct feeding injury to peanut plants, resulting in leaf chlorosis and curling, and yield loss. Adults and larvae also transmit the economically important tomato spotted wilt orthotospovirus (TSWV) in all peanut market types grown in the U.S. TSWV infection causes spotted wilt disease, a plant disease characterized by chlorosis, stunting, and death. From 1996 to 2006, spotted wilt disease resulted in an estimated U.S.$140 million in annual peanut production losses in the U.S. At present, a thorough documentation of F. fusca's impacts on the U.S. peanut production system is not available. Here, we describe the morphology, life cycle, and biology of F. fusca and provide images of immature life stages. Feeding injury characteristics and TSWV transmission in peanuts are also discussed. Currently, F. fusca and TSWV are managed in peanut with a combination of tactics, including prophylactic insecticide applications and TSWV-resistant cultivars. However, standardized scouting protocols and economic thresholds for F. fusca are not yet available. Very few biological control agents have been evaluated for use against F. fusca, and few studies have quantified the contributions of native natural enemies. More research into natural enemies' contributions to F. fusca management and the mechanisms underlying TSWV-resistance in peanut could help inform and diversify integrated pest management programs.