Weed-suppressive soils consist of naturally occurring microorganisms that biologically suppress a weed by inhibiting its growth and development. Increased knowledge of soil-pathogen-weed interactions can assist in identifying management practices that improve and enhance suppressiveness of soils, thereby promoting sustainable agroecosystems. Velvetleaf death and growth suppression was observed in a field (A) at the University of Nebraska Agricultural Research and Development Center (ARDC). Soils from several fields (including soilA) were collected from the ARDC and greenhouse studies were conducted to determine if these soils were biologically suppressive to velvetleaf. Surface-sterilized velvetleaf seeds were sown in pots containing the soils and emerging seedlings thinned to a constant three plants pot-1. Following eight weeks of growth, velvetleaf mortality was greatest (75%) and biomass was smallest (0.42 g/plant) in soilA compared to the other soils. In a second experiment to further test for a biological contribution to the suppressiveness of soilA, pots filled with soilA were either sterilized or not. Velvetleaf plants grown in sterilized soilA yielded a total biomass of 4.87 compared to 1.49 g/pot for the unsterilized soil. The high mortality and reduced growth observed in these experiments was attributed to pathogenic fungal species. To isolate the likely pathogen, number of colony forming units (cfu) of three soilborne pathogenic fungi (Rhizoctonia solani, Pythium species and Fusarium species) were measured in each pot using dilution plating. Results showed that soilA had 10 times as many cfu of Fusarium species (1.6 x 105 cfu/g soil) when grown in Nash-Synder Agar media for 2 days, as compared to other soils. Results indicate that a Fusarium species may negatively influence velvetleaf population biology. Further research is needed to identify the Fusarium species and evaluate its pathogenic effects on velvetleaf and its associated crop species.