evaluation of relative resistance of eleven maize hybrids against ostrinia nubilalis hb. (lepidoptera: pyralidae) in moghan region

european corn borer, ostrinia nubilalis hb. is a polyphagous insect, recognizing world widely as the predominant pest of maize. in this research the relative resistance of eleven hybrids of maize was evaluated in a field in agricultural and natural resources research center of moghan. this experiment was conducted in three replicates in a complete randomized block design. for comparison of the tested hybrids some traits including vertical tunnel length, number of vertical tunnel, larvae number in stalk, hole number in stalk, percentage of stalk breakage, and yield were used. the results showed that there was no significant difference among hybrids for vertical tunnel length, number of vertical tunnel, larvae number in stalk, and hole number in stalk. but, percentage of stalk breakage and yield were significantly different among the tested hybrids. the hybrids bc666, sc700 and sc704 with highest percentage of stalk breakage and low yield were the most susceptible hybrids and the hybrids exp1 and zp684 because of lowest percentage of stalk breakage and high yield were the most resistant hybrids. moreover, among the tested maize hybrids there were significant negative correlations between percentage of stalk breakage and yield. the result of this research could be useful in reducing pest damage in maize crop.