Abstract

The southern chinch bug (Blissus insularis Barber) adapted to the resistant turf cultivar, 'Floratam' St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] in Florida within 12 years after cultivar release.  The inheritance of host adaptation was studied in a crossing experiment involving reciprocal F₂ B. insularis crosses confined on 'Floratam.'  Interpopulation crosses (e.g. nonadapted X adapted) were intermediate in mean oviposition rate and longevity compared with parent populations. This proved that host adaptation was inherited and that different populations of southern chinch bug could readily interbreed.  Intercrosses among regional sources of adapted chinch bugs were well adapted to the resistant cultivar, thus host adaptation was controlled by the same genes, or similar gene action in different sources.  Host adaptation of chinch bugs was increased experimentally through selection on the resistant cultivar, as demonstrated by increased longevity on 'Floratam' in the F₃ generation from 'Floratam'-exposed, surviving F₂'s, compared with naive, nonexposed progeny.