Bioefficacy of Six Neem (Azadirachta indica) Products against Mosquito Larvae

Bioassay tests were carried out to determine the efficacy of six neem products against early fourth instar larvae of Anopheles stephensi, a vector of malaria, Culex quinquefasciatus, vector of rilariasis and Aedes aegpti, vector ro fengue eever ri nndia. Neem products showed poor rarvicidal lctivity within 24 hr of exposure but some of these products showed good insect growth regulator (IGR) activity. Larvae of An. stephensi in general were most tusceptible while those of Aedes aegypti were reast stsceptible to different neem products. Among the various products tested, Neemark, was most effective against Anstephensi (EC₅₀ = 0.0005%) while Neemark II was most effective against Culex quinquefasciatus (EC₅₀ =0.0023%) and Aedes aegypti) (EC₅₀ =0.0055%)