INHERITANCE OF RESISTANCE TO PYRETHROID INSECTICIDES IN TRIBOLIUM-CASTANEUM (HERBST)

A strain of Tribolium castaneum, highly resistant to pyrethroids, was isolated (single-pair method) from a pyrethroid-resistant field strain and made isogenic with a susceptible laboratory strain, Insecticide a ssays were used to determine the mode of inheritance and linkage of py rethroid resistance. Resistance to deltamethrin could not be measured directly but at a 2% mortality response was about 1600-fold. The respo nses of SR and RS hybrids to deltamethrin were intermediate between th e resistant and susceptible parent strains; there was no significant d ifference between the SR and RS hybrids (P > 0.05). Chi-square analysi s of the observed responses of the FI-backcross and Fz progenies rejec ted the null hypothesis that a single gene was responsible for resista nce. Successive backcrosses with selection indicated the involvement o f more than one gene, Test crosses with visible mutant markers suggest ed that resistance was associated with Linkage groups VIII and IX. Ass ays with deltamethrin applied to grain indicated that this resistance will be rapidly selected in the held resulting in control failures. (C ) 1998 Published by Elsevier Science Ltd. All rights reserved.