Host range expansion and increasing damage potential of Euwallacea nr. fornicatus (Coleoptera: Curculionidae) in Florida.

Ambrosia beetles in the Euwallacea nr. fornicatus complex (Coleoptera: Curculionidae) vector Fusarium spp. fungi pathogenic to susceptible hosts, including avocado, Persea americana Mill., (Lauraceae). Previous survey traps in Florida avocado groves indicated significant beetle populations in several groves with minimal observed beetle activity, suggesting an external beetle source. A natural area near one such grove revealed E. nr. fornicatus colonization of wild tamarind, Lysiloma latisiliquum (L.) Bentham (Fabaceae). A survey of the natural area was conducted to understand the role that natural areas might play in E. nr. fornicatus ecology in southern Florida. Headspace volatiles from rasped avocado and L. latisiliquum bark were analyzed by gas chromatography-mass spectroscopy (GC-MS) to identify potential attractants. Genetic analysis confirmed that these beetles and their symbiotic fungi are of the same complex that attacks Florida avocado. Gas chromatography-mass spectroscopy analysis indicated that avocado is high in α-copaene (a known attractant of E. nr. fornicatus), but this kairomone is lacking in L. latisiliquum. Host diam and ht were examined for potential influence on colonization behavior. Albizia lebbeck (L.) Bentham (Fabaceae) and an unknown shrub also were observed to be suitable hosts. Concurrent with this study, a nearby grove of soursop, Annona muricata L. (Annonaceae), was found to have infestations of E. nr. fornicatus. Euwallacea nr. fornicatus populations are increasing in Florida and other cultivated and native trees are potentially at risk. Further research is warranted to better understand the ecology of this emerging pest and the chemical cues used for host location. [ABSTRACT FROM AUTHOR]