The effect of weed density on the growth and reproductive performance of Zea mays everta using Euphorbia heterophylla as the test weed was investigated. The result of the experiment revealed that there was no significant difference between the control and the treatments, as well as among the treatments in the early growth performance of popcorn for the first four weeks of planting, but as from the fifth week upward, there was a significant difference between the control and the treatments as well as among the treatments and the difference was observed on the leaf length, leaf number, leaf width, stem girth and leaf dry weight. For the reproductive performance, there was significant difference between the control and the treatments but there was no significant difference among the treatments observed in the fruit number, cob weight, weight of 100 seeds, cob length and cob circumference, also there was no significant difference between the control and the treatments observed in the number of seed rows per cob.Istraživan je utjecaj broja jedinki korovne vrste Euphorbia heterophylla na rast i komponente prinosa kukuruza kokičara Zea mays var.everta. Prema rezultatu pokusa nije bilo značajne razlike između kontrole kukuruza bez korova i tretmana kukuruza s korovima tijekom prva četiri tjedna od sjetve. Nakon petog tjedna postojala je značajna razlika između kontrole i tretmana, naročito s gledišta duljine lista, broja listova, širine lista, obujma stabljike i masi suhog lišća. Kod komponenti prinosa uočene su značajne razlike između kontrole i tretmana s korovom, ali nije primijećena značajna razlika između tretmana unutar s korovom kako u broju plodova, masi klipa, masi 100 zrna, duljini klipa i opsegu klipa. Nije primijećena značajna razlika između kontrole i tretmana u broju redova zrna po klipu
