In the current study, 134 maize genotypes were screened against C. partelhls at MelkasarnAgricultural Research Center (MARC) under field and laboratory conditions.rnInitially, 134 maize lines against Chilo partelhls were screened based on the number ofrnleaf infestation and dead heart. From 134 lines tested in the field, 34 lines (.'010%rninfestation) showed promising in terms of C. partelhls resistance, 74 (11-25% infestation)rnlines were intermediate and the rest 20 lines (>25% infestation) were susceptible. Fromrneach category four lines were randomly selected and planted in tlu'ee replication usingrncompletely randomized design (CRD) to verify the plantsresult obtained under fieldrnscreening. Number of egg masses and leaf infestation per plant were recorded and thenrndissected to check for number of borer density, larvae exist holes and tunnel length.rnThere were significant differences for all parameters were observed among the threerncategories. Furthered more, the results confirmed the presence of similar trends with fieldrnscreening result in leaf infestation with screen house outcome.rnFinally, the growth and development of the borer were measured on the most susceptiblernand resistant maize lines which were de!ermined under natural, and m1ificial infestations.rnThese maizelines were examined for their relative resistance to the C. parfel!usrn(Swinhoe) in relation to feeding. Freshly hatched larvae of C. parfel!/ls were allowed torngrow on the leaf sheath and stem cuts of the two lines separately. The rate of growth, eggrnlying, egg hatchability, pupation, and adult emergence were studied. The insects showedrnbetter growth when reared on susceptible maize line than on the resistant line.rnThe majority of Ethiopian farmers have small land holdings. For these reasons, and thernhazards associated with insecticide applications, there is a great need to develop varietiesrnthat can resist pest attack with out requiring any traditional expenditure by the farmers.