VAPOR TOXICITY AND REPELLENCE OF SOME ESSENTIAL OILS AND TERPENOIDS TO ADULTS OF AEDES-AEGYPTI(L) (DIPTERA, CULICIDAE)

Bioefficacy of commercially used synthetic insecticides/repellents and potential of selected essential oils and terpenoids were assessed aga inst mosquitoes. Essential oils and terpenoids, were vapourised in com mercially manufactured mosquito repellent electronic assemblies and ef fects of such vapours were tested on 6-7 days old adult female Aedes a egypti. Commercially available 'mats' (coir rectangles) impregnated wi th allethrin were used as standards for comparison of Kt50 and Kt90 va lues. Fastest knock-down was seen in case of allethrin, followed by te rpeneol (anhydrous) and (-) carvone. Maximum knock-down time was obser ved for beta citronellol. All compounds exhibited a repellent effect a lso, terpeneol (anhydrous) being the best, followed by (-) carvone and citronellal. In repellent tests, no mortality was caused by terpenoid s, but allethrin caused > 80 per cent knock-down.