|CARILLO, DANIEL - University Of Florida|
|DUNCAN, RITA - University Of Florida|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2014
Publication Date: 11/18/2014
Citation: Carillo, D., Montgomery, W.S., Duncan, R., Kendra, P.E. 2014. Detection and management of Xyleborus glabratus and other vectors of laurel wilt, a lethal disease affecting avocados in Florida. Meeting Abstract. III Congress of the Latin American Association of Chemical Ecology; Bogota,Columbia (18-21 Nov 2014).
Technical Abstract: The redabay ambrosia beetle, Xyleborus glabratus, carries a phytopathogenic symbiont, Raffaelea lauricola, which causes laurel wilt, a lethal vascular disease of some Lauraceae species. Both X. glabratus and R. lauricola are natives of Asia that recently invaded much of the coastal plain of the southeastern USA. This new beetle-disease complex has decimated vast areas of native trees of the Lauraceae in the southeastern USA, and is now threatening the avocado industry in south Florida. Efforts to identify semiochemicals for early detection of this beetle and repellent substances to deter X. glabratus from avocado trees are described. Initial studies provided no evidence of an aggregation pheromone or attraction to ethanol, the standard attractant for ambrosia beetles. The existence of a sexual pheromone is unlikely because of the type of reproduction of these beetles. Males of X. glabratus, like many other ambrosia beetles, are flightless and never leave the beetle galleries where they mate with sibling or parental females. Females mate before engaging in dispersal and host seeking behaviors, making long range attraction between sexes unnecessary and unlikely. Therefore, research efforts concentrated on identification of economical kairomone-based attractants using essential oils high in sesquiterpenes for early detection of X. glabratus. Initially, manuka and phoebe oil lures proved to be attractive to X. glabratus. However, tests indicated that manuka lures are not very effective due to short field life, and phoebe lures are no longer available. Distilled cubeb oil lures were identified as a more effective tool for detection of X. glabratus, with a field life up to 3 months due to extended, low release of attractive sesquiterpenes, primarily a-copaene and a-cubebene (Kendra et al. 2014). In addition, screening of multiple compounds identified cyclic ketones as potential repellents for X. glabratus. However, the epidemiology of the laurel wilt disease in avocado groves is complex, apparently involving other species of ambrosia beetles capable of spreading the laurel wilt pathogen. Research demonstrated that other invasive and native ambrosia beetles also harbor the laurel wilt pathogen, apparently acquiring it when they breed in infected Lauraceae trees (Carrillo et al. 2014). These findings led to increased monitoring and management efforts aimed at resident ambrosia beetles. Typically, resident ambrosia beetles infest stressed trees; however, X. glabratus is a primary colonizer attacking healthy trees. The available evidence suggests that X. glabratus transmits laurel wilt to avocados or nearby Lauraceae trees but does not establish in avocado. Then, other ambrosia beetles breed in diseased trees and subsequently transmit the pathogen to new hosts. Current research aims to identify what factors mediate the attraction of resident ambrosia beetles and their activities spreading the laurel wilt disease in commercial avocado groves. References: (Please adhere to following models for articles and book chapters)- Carrillo D, Duncan RE, Ploetz J, Campbell A, Ploetz R, Peña JE. Lateral transfer of a phytopathogenic symbiont among native and exotic ambrosia beetles. Plant Pathol 2014; 63: 54-62- Kendra PE, Montgomery WS, Niogret J, Schnell EQ, Deyrup MA, Epsky ND. Evaluation of seven essential oils identifies cubeb oil as most effective attractant for detection of Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae). J Pest Sci 2014 (pub online 30 Jan)