Abstract: Asclepias syriaca, commonly called common milkweed native to North America is a perennial weed that has shown negative impacts on biodiversity and also as a competitive weed in cultivated fields. Common milkweed plants that naturally exhibited symptoms of wilting and necrosis were taken to isolate and identify the fungus. Based on DNA sequencing, this species was determined to be Colletotrichum sp. The experiment was conducted under laboratory conditions to determine the efficacy of treatment. Colletotrichum sp. was never isolated from the control plants, and none of them showed any symptoms. When the treatment was carried out at a concentration of 10⁷ spores/ml, common milkweed was able to show visible symptoms on its leaves. These findings suggest that fungi isolation from A. syriaca can be an effective biocontrol method in the future. While the results are encouraging, further studies are needed to optimize the pathogens application and ensure its environmental safety under field conditions. This research underscores the potential of fungal pathogens as eco-friendly alternatives to conventional weed control methods and contributes to knowledge on biological control strategies for invasive plant species.