Laurel Wilt Disease Associated With Redbay Ambrosia Beetle

Laurel wilt is a deadly vascular disease of plants in the laurel family (Lauraceae). It is caused by the fungus Raffaelea lauricola and vectored by the redbay ambrosia beetle, Xyleborus glabratus, apparently introduced from Asia in solid wood packing material into the Port of Savannah. Since 2003, laurel wilt has caused massive mortality of redbay (Persea borbonia) trees in the coastal plains of South Carolina, Georgia, and Florida, and more recently has spread to Alabama, Mississippi, North Carolina, Louisiana, and Texas. Other native forest species susceptible to the disease include swampbay (P. palustris - often considered synonymous with redbay), sassafras (Sassafras albidum), pondspice (Litsea aestivalis) and pondberry (Lindera melissifolia), a federally endangered species. As the disease spread inland, it has killed many scattered groups of sassafras in the absence of redbay, which may support broad disease spread to the north and west. Laurel wilt causes dieback in camphor trees (Cinnamomum camphora); an abundant species introduced a century ago from Asia. Avocado (Persea americana) also is susceptible to laurel wilt disease, which has been detected in the commercial production area in south Florida.

Laurel Wilt in Redbay
Laurel wilt disease in redbay. (L) Toothpick-like frass tubes extruded by ambrosia beetles boring into the wood. (C) Large redbay trees killed by laurel wilt, rotting and falling to the ground. (R) Black discoloration in sapwood, a typical symptom of laurel wilt in redbay trees. Photo Credit: GFC