Arthropod Community Associated with Tropical Soda Apple and Natural Enemies ofGratiana boliviana(Coleoptera: Chrysomelidae) in Florida

Abstract

ed States (Mullahey 1996). In pastures, tropical soda apple competes with forages resulting in re duced stocking rates (Mullahey et al. 1998). Flor ida ranchers spent an average of $44 per acre on chemical and mechanical control costs on tropical soda apple in 2006 (Thomas 2007). Additionally, this plant is an alternate host of several diseases of solanaceous crops (McGovern et al. 1994; Ad kins et al. 2007). herbivores and predators included hand catching, aspiration, rearing, and the use of beating cloths. Lepidopteran larvae found feeding on tropical soda apple were reared in the laboratory until adult emergence and then identified. Parasitoids were reared from G. boliviana pupae, and field observations of predation were made. Entomo pathogens of G. boliviana were identified using light microscopy by Dr. Drion Boucias at the Uni versity of Florida, and arthropods were identified by personnel at the Florida Department of Agri culture and Consumer Services, Division of Plant Industry (DPI), Gainesville, Florida, and the Sys tematic Entomology Laboratory, United States Department of Agriculture, Beltsville, Maryland. All arthropods collected from tropical soda apple from 1994 to 2011 are included in the DPI data base. A biological control program of tropical soda apple was initiated in 1994, and several natural enemies were collected in Brazil, Argentina and Paraguay (Medal et al. 1996), including Gratiana boliviana Spaeth (Coleoptera: Chrysomelidae). This host specific beetle was first released into Florida in May 2003, and by 2008 approximately 180,000 beetles had been released (Overholt et al. 2009). Experiments conducted in central Florida demonstrated that beetle populations increased during the summer and remained very low during the coldest months of the year from Dec to mid Mar (Overholt et al. 2010). Beetle populations were more abundant on plants located in open pastures compared to those in shaded hammocks (Diaz et al. 2011). In a four-year study, Overholt et al. (2010) demonstrated that tropical soda ap ple densities decreased by 90% two yr after beetle release. Survival from egg to adult in closed cages was 51% compared to 15% in open cages (Man rique et al. 2011), thus revealing the impact of bi otic factors on G. boliviana populations. Because of the presence in Florida of many solanaceous plants, we inventoried the herbivores associated with tropical soda apple with the hypothesis that many would expand their host ranges to include the novel resource. Additionally, because of the importance of G. boliviana as a biological control agent of tropical soda apple, we inventoried its natural enemies in Florida. A total of seven mite species and 75 species of insect herbivores were collected from tropical so da apple in Florida (Table 1). The host specificity of these species ranged from Solarium specialists to generalists and included major pests of agri cultural crops as well as ornamental plants. The high diversity of insect herbivores found in this study is explained in part by the presence of close tropical soda apple relatives in Florida, including 27 species in the genus Solanum and 31 species in other genera of Solanaceae (Wunderlin & Han sen 2008). Based on field observations, tropical soda apple is an attractive host for many agricul turally important insect pests such as Leptino tarsa decimlineata (Say) and L. juncta (Germar) (Chrysomelidae), Manduca sexta L. (Sphingidae), Bemisia tabaci (Gennadius) (Aleyrodidae), Aphis gossypii Glover (Aphididae) and Lineodes integra Zeller (Pyralidae) (Table 1), and therefore may serve as a reservoir on which pest populations may increase before moving into crops. A total of one mite species, 19 species of spiders and 30 species of predatory insects were found on tropical soda apple (Table 2). Predators observed feeding on G. boliviana larvae and pupae in cluded Geocoris punctipes (Say) (Lygaidae), Sinea sp. (Reduviidae), Perillis bioculatus (Fabricius), Stiretrus anchorago (Fabricius) (Pentatomidae), Tupiocoris notatus (Distant) (Miridae), Solenopsis invicta Buren (Formicidae), and the spider Peuce tia viridans (Hentz) (Oxyopidae). The mirid spe cies found in this study are facultative predators, Arthropods were collected from 2004 to 2011 at two G. boliviana mass rearing facilities in Fort Pierce, Florida and from several natural infesta tions on ranches or conservation areas in central and south Florida. Collection methods for insect