Efficacy of BAJ 2740, a new acaricidal tetronic acid derivative, against tetranychid spider mite species resistant to conventional acaricides

摘要

BAJ 2740 (ISO proposed common name: spirodiclofen) is a new acaricidal compound particularly active against spider mites, e.g. the two-spotted spider mite, Tetranychus urticae, and the European red mite, Panonychus ulmi. BAJ 2740 is a phenyl-substituted spirocyclic tetronic acid derivative, i.e. it belongs to a new class of chemistry. The compound is active against eggs, larvae, nymphs, all quiescent stages, and adult females. The baseline susceptibilities of several strains of T. urticae and P. ulmi were similar as shown by a larvae spray bioassay. BAJ 2740 was fully active to several strains of T. urticae showing resistance to organophosphates, hexythiazox, dicofol, clofentezine, pyridaben, fenpyroximate, abamectin and others. Additionally cross-resistance to organophosphates, hexythiazox and clofentezine was not detected in P. ulmi. Furthermore a field-derived population of T. urticae was artificially selected in the laboratory, but even after treatment of 29 generations resistance factors hadrisen only very moderately in this population.