The genus Marasmius is distributed worldwide, along with a precise identification of this fungus as a pathogen on the Imperata cylindrical plant, although its bioactive role is not well understood. The current work was designed to examine the population of Marasmius palmivorus and its antagonistic patterns. Sequencing the ITS genetic region of this fungus occurs through verifying the cladistics nature, and taxonomic validity, in addition to studying the antagonistic potential of this fungus. M. palmivorus (MG717877.1) was recorded in this plant, which represents a new finding in Iraq mycobiota. Data from the sequence alignment were used to plot a phylogenetic tree, using the Neighbor-Joining method (NJ) in molecular evolutionary genetics analysis based on Mega 7. Phylogenetic trees show a close relationship of 99% between this strain of M. palmivorus (MG717877.1) and international strains. On the other hand, the maximum antagonistic effect of M. palmivorus has been found to act against Fusarium solani and F. thapsinum, and to a lesser degree against Penicillium sp., T. harzianum, and P. cyclopium after 6 to 8 days of incubation. Results confirm the precise nomination of this taxon is M. palmivorus, which may act as a bioherbicidal and could be used as bioagent against various phytopathogenic fungi.