PATHOLOGY PROC. INTL. Soc. OTRICI.!LT. IX CONGR. 2000.1016-1017. Establishment of Two New Vectors of Citrus Pathogens in Florida Susan E. Halbert Division Plant Industry, Florida Department of Agriculture and Consumer Services, Gainesville, FL 32614 CoL. Niblett and K.L. Manjunath University of I"lorida, IFAS, Horticultural Sciences, Gainesville, FL 32611 Richard F. Lee Citrus Research and Education Center, University of Florida, iFAS, Lake Alfred, FL 33850 Lawrence G. Brown USDA, Raleigh, NC 27606 Additional index words. citrus greening disease, citrus tristeza virus, Diaplwrina citri, Toxoptera citricida Abstract. In the past 5 years, two homopteran pests of citrus have become established in Florida. Both are pests primarily because of their ability to transmit serious citrus pathogens. Brown citrus aphid [Toxoptera citricida (Kirkaldy)], the vector of citrus tristeza virus (CTV), was found in Florida in late 1995. The original infested area included parts of Dade and Broward Countiesin south Florida. Jn2 years, it had colonized most of peninsularFlorida. First finds in most counties were on outdoor citrus trees. The rate of colonization for brown citrus aphid in Florida was similar to the rate published for other invasive aphid species. Asian citrus psyllid [Diaphorina citri Kuwayama], the vector of citrus greening pathogens, was first found in Florida in June 1998. The original infested area included coastal Palm Beach County, and parts of northern Broward and southern Martin Counties. In 2 years, it colonized the southern half'ofthe Florida peninsula. In south Florida, Asian citrus psyllids could be found in the landscape, but in central Florida, only plants for sale in retail stores were found infested. Thus, it appears that the natural rate of colonization for Asian citrus psyllid is slowerthan that for brown citrus aphid; however, Asian citrus psyllid was more likely than brown citrus aphid to be moved on plants for sale in Florida. Surveys have been made for the pathogens transmitted by these pests. There is no evidence of citrus greening disease in Florida; however, we have seen an increase in both incidence and severity of CTV in areas where brown citrus aphid has been present 2 years fIr longer. Toxoptera citricida (Kirkaldy) is the most efficient vector of citrus tristeza virus (CTV). Introduction of Ihis aphid into various regions of Ihe Western Hemisphere has preceded serious outbreaks of CTV. Similarly, Diaphorina citri Kuwayama is a serious pest of citrus primarily because it is a vector of the pathogens that cause citrus greening disease or huanglongbing. Citrus greening has nOI been found in the Western Hemisphere, but D. cirri has been present in Soulh America for several decades. Florida is at risk for introductions of exotic pests and diseases due to the large amount of incoming commer- cial and tourist tramc. Additionally, Florida residents sometimes may smuggle plant materials from overseas. The Florida Department of Agriculture and Consumer Services, Division ofPlalll Industry (DPl), employs over 100 inspectors whose job it is to find new pests. This paper reports the establishment of two new citrus pests, D. citri and T. citricida. Prior to the arrival of T. citricida, there was a statewide baseline survey done to determine the incidence and make-up of CTV strains in Florida (Brown and Davison, 1997). No surveys had been done for citrus greening prior to the introduction of D. citri. Materials and Methods Surveys for new citrus pests were done in several ways. First. DPI and USDA inspectors monitored citrus in dooryards on a routine basis. Second, DPI inspectors monitored pests in nurseries and stock dealerships as part of their routine inspections. Third, after a new pest was detected. there was a special delimiting survey done by DPI inspectors. In the case of T. citricida, USDA inspectors also partici- pated. Surveys for CTV were done by collecting eight newly expanded leaves per tree, two per quadrant. The leaves either were ground fresh or petioles were extracted and dried prior to grinding and testing by enzyme-linked immunosorbant assay (ELISA). ELISA antibodies in- cluded a polyclonal mixture that detects all CTV and monoclonal antibody 13 (MCA-13), which detects most decline and stem-pitting CTV found in Florida. Visual surveys were conducted for citrus greening after the discovery of D. citri. Results and Discussion Toxoptera citricida was discovered in Florida in the late autumn of 1995 (Halbert et aI., 1998, 2000). The northern half of Miami-Dade County and the southern third of Broward County were found to be infested. We estimate that we detected the infestation within about m First find in the landscape First find in a retail store Fig. I. Distribution of Toxoptera citricida (Kirkaldy) in Florida. Nov. 2000. 1016 PROCEEDINGS OF THE INTER:'IATI01\:AL SOCIETY OF CITRICULTURE, DECEMBER 2000