Pyrethroid classes, acaricides

Pyrethroids, e.g. cypermethrin (89) and fenvalerate (90), are being employed. This class of compound is the result of structural manipulation by medicinal chemists of the naturally occurring pyrethrins (91) to overcome the latters photoinstability and lack of persistence when in use as ectoparasiticides. There are no heterocyclic representatives of this important class of insecticide/acaricide in use though many heterocyclic examples have appeared in the patent literature. 

This chemical is used for the control of cone worms, seed bugs, seed worms, and other insects and mites. The USEPA has classified bifenthrin as toxicity class II, meaning it is moderately toxic.4,5 Bifenthrin is a member of the pyrethroid chemical class. It is an insecticide and acaricide that affects the central nervous system (CNS) and causes paralysis in insects.6,7 It is highly toxic to fish and aquatic organisms. 

Neurotoxic compounds have been traditionally the largest category of acaricides, with several representatives from the organophosphate, carbamate, and pyreth-roid classes. Several new pyrethroid compounds such as acrinathrin, lubrocythri-nate and halfenprox and an analog of the macrolide abamectin milbemectin were recently introduced as acaricides. A completely new acaricidal chemistry has been found with carbazate chemistry [1]. 

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