The presence of weeds has an effect on the insect abundance in the crop ecosystem, which affects the pest management
practices. This paper reports the abundance of Asiatic corn borer, Ostrinia furnacalis Guenee, egg masses and parasitism by its
native egg parasitoid, Trichogramma papilionis Nagarkatti, in two vegetational regimes namely weedy (plot with natural
weed) and weed-free (plot without weed). The results showed that there was no significant difference in the total number of
egg masses laid in weedy and weed-free plot, however, the number of parasitized egg masses was significantly higher in the
weedy plot than the weed-free plot (72 and 50%, respectively). The higher number of parasitized egg masses in weedy plot
reduced the number of holes bored by O. furnacalis on corn stalks and that the number of corn borer present inside the stalks
as compared to those in the weed-free plots. Results of this study suggest that an establishment of weeds in corn ecosystem
could be an important strategy in enhancing the effectiveness of T. papilionis in controlling the Asiatic corn borer.