ABSTRACT

Pyrethrum insecticide is derived from the flowers of Chrysanthemum cinerariaefolium Vis., and has been used for centuries to control insects (McLaughlin 1973). Pyr-ethrum extract is recognized to contain six insecticidal esters (Figure 8.1) (Dev and Koul 1997), whose mode of action primarily involves altering the function of the voltage-sensitive sodium channel in nerve axons (Soderlund and Bloomquist 1989). It is highly toxic to insects, and so can be used at rates lower than those recommended for most synthetic insecticides. In addition, it has very good knockdown properties, making it highly desirable for domestic use.