Dispersal by horn flies, Haematoma irritans (L.), may have a significant impact on management of insecticide resistance. Recent discovery of extensive movement of horn flies between cattle herds separated by 0.05, 0.8, and 1.7 km is used as a basis for consideration of a new resistance management strategy for this pest. Use of a mosaic in which insecticides are applied in different sectors of a grid pattern may delay resistance in highly mobile insects with relatively specific host/habitat requirements. The mechanism by which resistance is managed is similar to action of insecticide mixtures if there is extensive movement between treated sectors within a generation. Resistance is delayed by a process analogous to insecticide rotations if movement between treated sectors occurs between generations. Current evidence indicates that newly emerged horn flies are primarily responsible for dispersal so that a mosaic would function principally as a rotation of insecticides. The practicality and data base required to employ mosaics successfully are compared with the strategies of mixtures and rotations.