title: Spatiotemporal dynamics of the Southern California Asian citrus psyllid (Diaphorina citri) invasion.
abstract: Biological invasions are governed by spatial processes that tend to be distributed in non-random ways across landscapes. Characterizing the spatial and temporal heterogeneities of the introduction, establishment, and spread of non-native insect species is a key aspect of effectively managing their geographic expansion. The Asian citrus psyllid (Diaphorina citri), a vector of the bacterium associated with huanglongbing (HLB), poses a serious threat to commercial and residential citrus trees. In 2008, D. citri first began expanding northward from Mexico into parts of Southern California. Using georeferenced D. citri occurrence data from 2008-2014, we sought to better understand the extent of the geographic expansion of this invasive vector species. Our objectives were to: 1) describe the spatial and temporal distribution of D. citri in Southern California, 2) identify the locations of statistically significant D. citri hotspots, and 3) quantify the dynamics of anisotropic spread. We found clear evidence that the spatial and temporal distribution of D. citri in Southern California is non-random. Further, we identified the existence of statistically significant hotspots of D. citri occurrence and described the anisotropic dispersion across the Southern California landscape. For example, the dominant hotspot surrounding Los Angeles showed rapid and strongly asymmetric spread to the south and east. Our study demonstrates the feasibility of quantitative invasive insect risk assessment with the application of a spatial epidemiology framework.
authors.affiliation: Department of Entomology, University of California Riverside, Riverside, California, United States of America.|School of Health and Natural Sciences, Dominican University of California, San Rafael, California, United States of America.
authors.forename: Brett R
authors.identifier: http://orcid.org/0000-0002-3474-4353
authors.initials: BR
authors.lastname: Bayles
authors.affiliation: Department of Entomology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Shyam M
authors.initials: SM
authors.lastname: Thomas
authors.affiliation: United States Department of Agriculture, Animal and Plant Health Inspection Service, Salinas, California, United States of America.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Simmons
authors.affiliation: Department of Entomology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Grafton-Cardwell
authors.affiliation: Department of Entomology, University of California Riverside, Riverside, California, United States of America.
authors.forename: Mathew P
authors.initials: MP
authors.lastname: Daugherty
mesh_terms: D000818:Animals; D002140:California; D002957:Citrus / Q000821:virology*; D006430:Hemiptera / Q000472:pathogenicity*; D062211:Spatio-Temporal Analysis