The entomopathogenic nematodes, Steinernema carpocapsae (All strain), Heterorhabditis bacteriophora (HP-88 strain), H. bacteriophora (Florida strain), applied to the soil of a citrus grove near Lake Jem, Florida in March 1989, significantly reduced adult emergence of the root weevil, Diaprepes abbreviatus (L.). The total number of weevils captured in 160 traps from April 1989 through May 1990 was 833. Weevil emergence was reduced 70% compared with the check in May, June, and September (1989) and March and April 1990. There was no difference between nematode treatments. Efficacy trials conducted in a grove in Fort Pierce, Florida, for control of the citrus root weevil, Pachnaeus opalus and P. litus, gave similar results. A study to determine seasonal variation of a native heterorhabditid population in a grove adjacent to the Lake Jem grove was inconclusive.