THE INTRODUCTION, ESTABLISHMENT, AND SPREAD OF ORMIA-DEPLETA IN FLORIDA

Ormia depleta (Wiedemann) (Diptera: Tachinidae), native to Brazil, is a parasitoid of some Scapteriscus species (Orthoptera: Gryllotalpidae) . It was first cultured in a laboratory in Florida in 1987. Releases o f O. depleta were made against Scapteriscus mole crickets in all regio ns of Florida beginning in 1988. Establishment of populations was achi eved at some, but not all, of the release sites. The two earliest-esta blished populations were monitored using traps employing synthetic cal ling song of male Scapteriscus mole crickets, to which gravid female f lies are attracted. Additionally, progeny of the released flies were t rapped between 1988 and 1993 in 32 peninsular counties, including 15 c ounties in which no releases had been made. The most parsimonious expl anation of the pathways of spread of the current population was inferr ed from trapping surveys, and this yielded the probable year of coloni zation for peninsular counties. Reports in successive years by golf co urse superintendents of damage by mole crickets showed that counties w ith O. depleta populations had significantly less damage than did yet- uncolonized counties. (C) 1996 Academic Press, Inc.