Tralomethrin (OMS-3048), a new synthetic pyrethroid against vector mosquitoes

Tralomethrin (OMS-3048) a synthetic pyrethroid, was tested for its insecticidal properties in the laboratory against normal strains of Culex quinquefasciatus, Cx. tritaeniorhynchus, Cx. sitiens, Anopheles stephensi, An. culicifacies, Aedes aegypti and Armigeres subalbatus and against strains of Cx. quinquefasciatus resistant to fenthion and malathion. Tralomethrin showed good larvicidal activity against all the species tested. LC50 ranged between 7.00 x 10(-6) and 9.10 x 10(-3) mg (ai)/l. Resistant strains of Cx. quinquefasciatus showed higher tolerance than the normal strain. Tralomethrin was more effective against adults of An. culicifacies (LD50 0.18 micrograms/cm2) than the other species. Residual activity of this compound lasted for 15 weeks on thatch surface at a dosage of 50 mg (ai)/m2 against all the mosquito species tested. In the field, this compound was effective for a period of 1-2 days in polluted water viz., cesspits and drains and 10-24 days in less polluted water as in cement tanks, when applied at the rate of 0.002-2.0 mg (ai)/l against immatures of Cx. quinquefasciatus.