Present status and future prospects for synthetic pyrethroids

The potential number of insecticidally active variations of compounds with a discernible relationship to pyrethrin I is continually increasing as new acid, alcohol, and other components, many of them asymmetric, are discovered. Knowledge of how structure affects activity for important practical uses (activity against pest species, acaricidal activity, selectivity between pests and beneficial species, persistence on crops and in the environment, rapidity of action, antifeedant or repellent properties, toxicity to mammals, birds and fish, etc.) is being rapidly accumulated. Although strictly such information can only be obtained by direct testing of many related compounds, broad conclusions about the physical properties that influence the behaviour of pyrethroids in the environment can be predicted from their structures. As with applications of such procedures to other groups of pesticides, most results are precise only within an order of magnitude but these nevertheless provide a basis for valuable generalisations. The prospects for developing pyrethroids with properties especially appropriate for particular insect control applications are therefore encouraging, and the scope of pyrethroids may become comparable with those of the longer established groups of insecticides
RESP-8661