Establishment ofHydrellia pakistanae(Diptera: Ephydridae) for the Biological Control of the Submersed Aquatic PlantHydrilla verticillata(Hydrocharitaceae) in the Southeastern United States

The Indian leaf-mining flyHydrellia pakistanaeDeonier was released in the United States during October 1987 as a potential agent for the biological control of the submersed aquatic plant,Hydrilla verticillata(L.f.) Royle. Since then, nearly 3 million individuals have been released in four states at over 25 separate locations.Hydrellia pakistanaeis now permanently established at many locations in Florida as well as other portions of the southeastern United States. Despite early failures, populations established from at least 70% of the release attempts. Modifications of rearing and release procedures that considered the biology of the agent in relation to various habitat characteristics facilitated successful establishment.