Survival and growth was measured for five geographically distinct strains ofScirpophaga incertulas(Walker) (the yellow stem borer) reared on three wild species of rice (Oryza nivara, O. barthii, andO. officinalis), three traditional cultivars ofO. sativarice (‘C018’, ‘W1253’, and ‘Rexoro’), and three modern, high yielding rice (O. sativa) cultivars (‘IR56’, ‘IR40’, and ‘IR62’). All yellow stem borer strains showed differential survival and weight gain across the nine rice hosts. There were significant differences in mean survival of the five stem borer strains on all of the rice hosts except two wild rices,O. nivaraandO. officinalis, where all five strains had similar survival. Statistically significant host-by-strain interaction in both survival and weight indicates that differences among populations of theS. incertulaswere host-dependent and were most likely the result of genetic differentiation. There was some indication of similarity between geographically related stem borer strains, but this was not consistent. The importance of these findings to the development of strategies for deploying rice varieties with resistance toS. incertulasis discussed.