Abstract
A strain of housefly, Wakamatsu-m, highly resistant to malathion, was established from a colony collected in Kitakyushu after 13 generations of successive selection with this chemical. The resistance was shown to be almost completely dominant by the reciprocal crosses between the resistant and susceptible strains. Linkage group analysis of the dominant factor responsible for this resistance was carried out by the method F1 male backcross to susceptible multi-chromosomal marker strains. The dominant factor for malathion resistance was located only on the 2nd chromosome and no dominant effect of the other autosomes was observed. For toxicological characterization of the resistant strain used, results of susceptibility tests with various groups of insecticides are also given.
