Objectives: To determine growth regulating hormone methoprene larvicide's activity. Design: Experimental study. Setting: Instituto de Investigacion de Ciencias Biologicas Antonio Raimondi, Facultad de Ciencias Biologicas, Universidad Nacional Mayor de San Marcos. Sub-Region de Salud de Madre de Dios. Centro de Investigacion Biologica para el Desarrollo Amazonico. Biologic material: Stages III and IV Aedes aegypti larves. Interventions: Three laboratory bioessays were done to determine regulating hormone methoprene (Altosid)® on 7 000 stages III and IV Aedes aegypti larves, in the laboratory and in Anopheles benarrochi natural breeding places. Larval population was obtained from breeding places located in La Cachuela, La Joya and Las Piedras communities, Tambopata province (Puerto Maldonado), Madre de Dios department. Larvicide activity was determined by 2 methoprene doses, 0,004 and 0,0...