Toxicity of newly synthesized pyrethroids against the yellow fever mosquito larvae, Aedes aegypti (Diptera: Culicidae).

Synthesis of p-substituted benzyl esters of (+/-) cis 2,2-dimethyl-3-(2,2-dichlorovinyl)cyclopropane-carboxylic acid has been reported. (+/-) cis Dichlorovinyl acid esters of p-substituted phenols acquired insecticidal activity after introduction of methylene group. The insecticidal activity shown against mosquito larvae A. aegypti by compounds having electron withdrawing groups such as -NO2, -CN was substantially higher than that of the compounds having electron-donating groups such as -CH3, -OCH3.

Mosquito repellent activity of oils from Vitex negundo Linn. leaves.

Oil obtained from stream distillate of V. negundo leaves was fractionated by column chromatography. Mosquito repellence activity, as evaluated against Aedes aegypti was mainly confined to the most polar fractions. The protection period against mosquito bites by polar fractions ranged between 1-3 h. However, the mean protection period values of these fractions did not show significant increase in the subsequent subfractions.