The tank bromeliad Billbergia pyramidalis was treated with 2 doses (0.5 and 2 g) of ALTOSID Granules or Pellets for the control of Aedes aegypti L. Emergence inhibition (EI) for all mosquito pupae (including natural populations) in the center wells and leaf axils was > 90% for at least 6 and 12 months for both doses of granules and pellets, respectively. No significant difference in %EI was found between center wells and leaf axils.