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Poster: Diseases of Plants: New & Emerging Diseases


The laurel wilt story: introduction and impact of an exotic vector (Xyleborus glabratus) and pathogen (Raffaelea lauricola)
M. HUGHES (1), J. Riggins (2), A. cognato (3), F. Koch (4), C. Anderson (5), T. Dreaden (6), J. Formby (2), R. Ploetz (7), J. Smith (8) (1) University of Florida, School of Forest Resources and Conservation, U.S.A.; (2) Mississippi State University, Depar

Laurel wilt is a lethal vascular disease that affects plants in the Lauraceae family. Since the exotic vector (Xyleborus glabratus) and its pathogenic fungal symbiont (Raffaelea lauricola) were introduced to the USA in 2002, laurel wilt has killed redbay (Persea borbonia) and related trees in southern forests. Many questions remain about the disease in the USA, including the number of introduction events, the genetic diversity of the vector and pathogen, and how many host trees have died. To infer the number of introduction events and assess genetic variability, Amplified Fragment Length Polymorphism (AFLP) markers were used to screen a collection of R. lauricola isolates, and a portion of the cytochrome oxidase I (COI) gene was sequenced and compared for X. glabratus samples. Results suggest that R. lauricola and X. glabratus are both clonal organisms in the USA that were likely introduced in a single event. Forest Inventory and Analysis (FIA) data were used to obtain pre- and post-epidemic redbay population levels, which were then used to calculate redbay mortality due to laurel wilt. The FIA data suggest that laurel wilt has spread over 250,000 km2 and killed nearly half a billion redbay trees. These data highlight the devastating impact that invasive organisms can have on native forests.