A sand granule formulation of methoprene (SAN 810 I 1.3 GR) was tested in outdoor intermittently flooded pools as a pre- and postflood treatment for the control of Aedes taeniorhynchus. In field test 1, pre- and postflood treatments were equally effective. Inhibition of emergence in mosquitoes exceeded 90% for one and 3 flood/dry cycles when SAN 810 I 1.3 GR was applied at rates of 2.8 and 5.6 kg/ha, respectively. In field test 2, > 90% inhibition of emergence was achieved only when SAN 810 I 1.3 GR was applied postflood at 5.6 kg/ha.