ENSC 201 Lecture Notes - Lecture 13: Allethrins, Tetramethrin, Permethrin
17 Aug 2016
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If pesticide must be non-persistent, may need to be more toxic: organophosphates are older but good example. Mode of action is neurotoxicity through inhibition of acetylcholinesterase: nerves that fire release acetylcholine, then ache enzyme removes acetylcholine, without enzyme, nerve synapse can"t reset, get paralysis. Problem this enzyme is also in many non-target organisms, including humans. Modern approach: if non persistent, must have high acute toxicity: to avoid hazard, toxicity must be more selective, learn from nature, insecticides pyrethrins. Isolated from chrysanthemum some plants have evolved over many years to have natural defense against insects: pyrethins low toxicity to humans, can be used indoor (domestic), short term outdoors. Not stable enough for agriculture use: commercial synthetic variations on natural structure are more stable. Still not persistent: raid" uses allethrin, permethrin and other pyrethrins, moderate toxicity to insects requires extended exposure needs regular application or improved technology (can include wax to coat pests and stabilize while delivering over longer time)
