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THE DEVELOPMENTAL EFFECTS OF 6, 7‐DIMETHOXY‐2, 2‐DIMETHYL CHROMENE ON THE PRE‐IMAGINAL STAGES OF AEDES AEGYPTI (DIPTERA: CULICIDAE)

The effects of 6, 7‐dimethoxy‐2, 2‐dimethyl chromene (precocene II) on pre‐imaginal development in Aedes aegypti were determined by exposure of eggs, larvae and pupae to this botanically derived compound. Precocene II prevented adult emergence when newly hatched larvae were exposed to dosages ranging from 2 to 4 ppm. Pupation was inhibited when early 4th‐instar larvae were exposed to dosages ranging between 1 and 10 ppm. Fourth‐instar larvae treated at concentrations above 0.1 ppm, also required more time to complete metamorphosis than controls. The pupal and egg stages were insensitive to treatments at concentrations up to 10 ppm.