The susceptibility of head lice, Pediculus humanus capitis collected from children in Israel and that ofa laboratory colony of body lice, Pediculus humanus humanus to the insecticides malathion, deltamethrin, permethrin, fenitrothion and dieldrin has been evaluated using standard WHO papers. The LT50 and LT95 were established using different exposure times. Deltamethrin had the highest“knock-down”effect, followed by permethrinand malathion. All insecticidesexcept dieldrin gave higher mortality for body lice than for head lice. No differences in the susceptibility between adult and nymph lice could be observed.
