Evaluation of organic infusions and synthetic compounds mediating oviposition in Aedes albopictus and Aedes aegypti (Diptera: Culicidae)

Oviposition responses of gravid Aedes albopictus and Ae. aegypti were evaluated to natural organic infusions (hay infusion, larva: rearing water, and field-collected larval water) as well as compounds isolated from hay infusion (3-methylindole, 4-methylphenol, 4-ethylphenol, indole, and phenol) known to elicit oviposition in Culex mosquitoes. In laboratory bioassays, significant oviposition responses were obtained from Ae. albopictus, but not from Ae. aegypti, to dilutions of hay infusion and field water. Oviposition responses of both species were moderate to the synthetic compounds tested in the laboratory (0.01-100 mu g/liter). Only 3-methylindole (0.1 mu g/liter) and 4-ethylphenol (1.0 mu g/liter) elicited significantly more oviposition by Ac. albopictus than did well water. Of the synthetic compounds rested with Ae. aegypti, only phenol (1.0 mu g/liter) and 4-ethylphenol (0.1 mu g/liter) elicited significantly more oviposition than did well water. Significant repellency or oviposition deterrence for both species occurred in response to at least one high concentration of most of the compounds tested. In field cage evaluations, oviposition responses by Ae. albopictus were strongest to larval water and field water, moderate to hay infusion and 3-methylindole (100 mu liter), and low to well water. A mixture of five synthetic compounds mimicking hay infusion was no more effective than 3-methylindole alone. For Ae. aegypti, oviposition responses were greatest to larval water and least to 3-methylindole. In an olfactometer, gravid females of both species oriented mon to field water than to well water and only Ae. albopictus oriented more to larval water or hay infusion than well water. In general, gravid Ac. albopictus responded more strongly to oviposition stimuli than did Ae. aegypti.