Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 19, 2011
Publication Date: December 15, 2011
Citation: Niogret, J., Kendra, P.E., Epsky, N.D., Heath, R.R. 2011. Comparative analysis of terpenoid emissions from Florida host trees of the redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: scolytinae). Florida Entomologist. 94(4):1010-1017. Interpretive Summary: The redbay ambrosia beetle is an exotic wood-boring insect that vectors a fungal pathogen responsible for laurel wilt, a new lethal disease of avocado and related trees that threatens avocado production. Host-based chemicals provide the best source for development of attractants critically needed to detect, monitor, and control the spread of this invasive pest. Therefore, scientists at SHRS analyzed the chemical profiles of avocado and related host trees (redbay, swampbay, silkbay, camphor tree and lancewood) and compared them to chemical profiles of lychee, a highly attractive non-host tree identified in previous research. Chemical analysis identified 9 compounds common to all 6 host trees including 3 that are also found in lychee. The results of this research will be used to identify host wood sources with high levels of these chemicals for use in field tests and laboratory bioassays, to evaluate their potential as attractants for this pest, and to develop synthetic host-based lures. Newly developed lures will be used by regulatory agencies and growers for improved detection and pest management of this pest, which will provide new methods to control the spread of this lethal plant disease.
Technical Abstract: The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), is an exotic wood-boring insect that vectors Raffaelea lauricola, the fungal pathogen responsible for laurel wilt, a lethal disease of trees in the Lauraceae. First detected in the U.S. near Savannah, GA in 2002, X. glabratus has since spread throughout the southeastern coastal plain causing high mortality in native Persea species, particularly redbay (P. borbonia) and swampbay (P. palustris). Currently, breeding populations of X. glabratus pose an imminent threat to the avocado (P. americana) industry in south Florida. There is a critical need for effective attractants to detect, monitor, and control the spread of this invasive pest. In an effort to identify host-based attractants for dispersing female X. glabratus, we conducted a comparative study of the volatile chemicals emitted from wood of six species of Lauraceae found in Florida: avocado, redbay, swampbay, silkbay (P. humilis), camphor tree (Cinnamomum camphora), and lancewood (Ocotea coriacea). We compared chemical profiles to those obtained from wood of lychee, Litchi chinensis (Sapindaceae), a presumed non-host found to be highly attractive to X. glabratus in field tests. GC-MS analysis identified 9 terpenoid compounds common to all lauraceous species. Of these, three sesquiterpenes were also found in lychee: a-copaene, ß-caryophyllene and cadinene. Future research will include field tests and laboratory bioassays to evaluate the roles of each of these potential kairomones.