Detoxification Esterases New to California, USA, In Organophosphate-Resistant Culex Quinquefasciatus (Diptera: Culicidae)1

Abstract
Electrophoretic analysis of some Californian populations of Culex quinquefasciatus sampled in 1984 and 1985 revealed 2 highly active esterases (A2 and B2) not previously observed in California. These esterases are involved in organophosphate resistance but are less efficient than the previously described esterase B1 coded by the Est-2ˆ gene. The possible origin of these new esterases is discussed.