Ion channels are the primary target sites for several classes of natur
al and synthetic insecticidal compounds. The voltage-sensitive sodium
channel is the major target site for DDT and pyrethroids, the veratrum
alkaloids, and N-alkylamides. Recently, neurotoxic proteins from arth
ropod venoms, some of which specifically attack insect sodium channels
, have been engineered into baculoviruses to act as biopesticides. The
synthetic pyrazolines also primarily affect the sodium channel, altho
ugh some members of this group target neuronal calcium channels as wel
l. The ryanoids have also found use as insecticides, and these materia
ls induce muscle contracture by irreversible activation of the calcium
-release channel of the sarcoplasmic reticulum. The arylheterocycles (
e.g. endosulfan and fipronil) are potent convulsants and insecticides
that block the GABA-gated chloride channel. In contrast, the avermecti
ns activate both ligand- and voltage-gated chloride channels, which le
ads to paralysis. At field-use rates, a neurotoxic effect of the ecdys
teroid agonist RH-5849 is observed that involves blockage of both musc
le and neuronal potassium channels. The future use of ion channels as
targets for chemical and genetically engineered insecticides is also d
iscussed.