The Impacts of Prescribed Burning on Vectors of Laurel Wilt in Post Outbreak Forests in South Carolina, USA

Abstract

Laurel wilt (LW) is a nonnative, invasive disease complex caused by the fungal pathogen Harringtonia lauricola and primarily vectored by the redbay ambrosia beetle (Xyleborus glabratus). This disease was first reported in the United States in 2002 and has caused the mortality of hundreds of millions of trees in the Lauraceae family. Currently, there are no successful management strategies for controlling LW at the forest scale, but prescribed burning presents a promising option for managing LW in fire prone ecosystems. To assess the efficacy of prescribed burning to control LW and its ambrosia beetle vectors, we conducted a study in a post-LW forest in South Carolina. We established multiple plots to determine the colonization and emergence rates of H. lauricola vectors and the population of ambrosia beetles (Coleoptera: Curculionidae) attracted to Lauraceae volatiles. Additionally, tissue samples were collected from redbay (Tamala borbonia) trees within plots to test for the presence of H. lauricola and track the incidence of LW before and after prescribed burns. Our results indicate that prescribed burns do not affect population dynamics of H. lauricola vectors or incidence of LW in forests where prescribed burns are regularly conducted. However, prescribed burning may influence host physiology, which impedes LW vectors host detection and reproduction.