Four developmental inhibitors (Altosid, Altozar, ZR-619 and ZR-777) and two organophosphates (Parathion and Abate) were tested on Aedes aegypti under laboratory conditions. When applied to fourth-instar larvae, the organophosphates were more toxic than the developmental inhibitors. Concentrations required for standard kills (LC50 and LC95) were lower for Altosid and ZR-619 than for Altozar and ZR-777. Field applications of Altosid SR-10 controlled Culiseta inornata for two weeks at 4 ounces per acre. With the exception of Dolichopodidae, most non-target aquatic organisms showed little response to Altosid SR-10. Although the developmental inhibitors Altosid and ZR-619 require higher concentrations for mosquito control, they inflict a minimum amount of damage to non-target aquatic organisms.