Location: Subtropical Horticulture ResearchTitle: Host range expansion and increased damage potential of Euwallacea nr. fornicatus (Coleoptera: Curculionidae) in Florida Author
|Owens, David - Orise Fellow|
|Cruz, Luisa - University Of Florida|
|Duncan, Rita - University Of Florida|
|Carrillo, Daniel - University Of Florida|
Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2018
Publication Date: 6/20/2018
Citation: Owens, D., Cruz, L., Montgomery, W.S., Narvaez, T.I., Schnell, E.Q., Tabanca, N., Duncan, R., Carrillo, D., Kendra, P.E. 2018. Host range expansion and increased damage potential of Euwallacea nr. fornicatus (Coleoptera: Curculionidae) in Florida. Florida Entomologist. 101(2):229-236.
Interpretive Summary: A complex of Asian ambrosia beetles (collectively referred to as Euwallacea near fornicatus) have become established recently in Florida, California, and Israel, where they are pests of avocado. These wood-boring beetles carry a fungus that causes branch dieback disease, reducing fruit production in infected trees. Scientists from the USDA-ARS (Miami, FL), in collaboration with the University of Florida (Homestead), conducted a survey in 2016 to determine the prevalence of this pest in the avocado production area in Miami-Dade County, Florida. Although avocado appeared to be the preferred host, the beetle was also found to breed successfully in wild tamarind (Lysiloma latisiliquum). This is the first report of a Florida native tree capable of functioning as a reservoir host, harboring E. nr. fornicatus that may disperse and infest nearby avocado groves. Chemical analysis of Lysiloma wood also identified potential new attractants. This research improves our understanding of the ecology and host preferences of this emerging pest in South Florida, and benefits avocado growers and action agencies that survey for E. nr, fornicatus in commercial groves.
Technical Abstract: Ambrosia beetles in the Euwallacea nr. fornicatus complex (Coleoptera: Curculionidae) vector Fusarium spp. fungi pathogenic to susceptible hosts, including avocado. The Florida avocado production area in Miami-Dade County was surveyed for E. nr. fornicatus upon observations of initial damage in 2016. Traps in several groves indicated significant beetle populations, but minimal activity was observed on avocado, suggesting the presence of other hosts in near proximity. At one grove, large numbers of E.nr. fornicatus were discovered in an adjacent natural area, and the majority of beetles were colonizing wild tamarind, Lysiloma latisiliquum (L.) Bentham (Fabaceae). Genetic analysis confirmed that these beetles and their symbiotic fungi are of the same complex that attacks Florida avocado. GC-MS analysis indicated that avocado is high in a-copaene (a known attractant of E. nr. fornicatus), but this kairomone is lacking in L. latisiliquum. Gallery density in L. latisiliquum was estimated and data were collected to assess effects of host diameter and height on the site of beetle attack. 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. It is apparent that population levels of E. nr. fornicatus are increasing in Florida and that other cultivated fruit trees and native species are potentially at risk. Further research is warranted to better understand the ecology of this newly emerging pest and the chemical cues utilized for host location.