PROINSECTICIDES EFFECTIVE AGAINST INSECTICIDE-RESISTANT PEACH-POTATO APHID (MYZUS-PERSICAE (SULZER))

A range of potential proinsecticides was synthesised and tested agains t insecticide-susceptible and -resistant clones of Myzus persicae (Sul zer). They were all esters of compounds known to be toxic or pharmacol ogically active, and were designed to have increased lipophilicity and to be subject to more rapid activation by hydrolysis in resistant tha n in susceptible aphids due to the increased amount of esterase presen t in the resistant clones. The most potent toxins were esters of monof luoroacetic acid. When applied topically, the toxicity of these esters to M. persicae was directly proportional to the esterase content of t he aphids. Such compounds would not be suitable as commercial insectic ides, but the results serve to illustrate the potential benefits of ex ploiting a resistance mechanism against one class of compounds to rend er another class more toxic, i.e. to design compounds that show negati ve cross-resistance. (C) 1998 SCI.