Assessment of the residual efficacy of lambda-cyhalothrin. 1. A laboratory study using Anopheles arabiensis and Cimex lectularius (Hemiptera: Cimicidae) on treated daub wall substrates from Natal, South Africa.

Laboratory assessment of the residual efficacy of lambda-cyhalothrin (Icon) 10% AI against Anopheles arabiensis and Cimex lectularius was carried out. The insecticide was applied to daub substrates, simulating the wall surface of houses from 3 areas within the endemic malaria area of Natal, South Africa. Variability in residual efficacy was found between different areas and appeared to correlate to organic content of the substrate. Residual efficacy against An. arabiensis ranged from as little as 2 wk in some areas to in excess of 14 wk in others. Residual efficacy against C. lectularius was 4 wk for all 3 areas, but was 10 wk in only 2 areas.