Recent Examples of pyrethrin from the Web
As if that's not reason enough to avoid them, those insecticidal shampoos often don't even work any more, because so many lice have also become resistant to pyrethrins and pyrethroids.
Most wasp killers contain pyrethrins, which are derived from botanical sources.
The Extension recommends using a fast-acting aerosol insecticide containing pyrethrins if fire ants are detected among flood debris, though these insecticides can be toxic to aquatic organisms, so caution is recommended.
Pyrethrins and pyrethroids also work by interfering with sodium pores.
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