Insensitive acetylcholinesterase and resistance to organophosphates in Australian Helicoverpa armigera

Organophosphates are valuable insecticides used to control Helicoverpa armigera on cotton in Australia. Those most commonly used for Helicoverpa spp. control are profenofos, parathion-methyl and chlorpyrifos. However, there is an emerging organophosphate-resistance threat in Australian H. armigera, which is compounded by cross-resistance between profenofos and parathion-methyl. An insensitive acetylcholinesterase has been identified as the common resistance mechanism. No resistance to chlorpyrifos has been detected and acetylcholinesterase remains fully sensitive to the chlorpyrifos oxon. (C) 1998 Society of Chemical Industry.