A point intercept survey was conducted from 2005 to 2010 on the Ross Barnett Reservoir near Jackson, MS to calculate the frequency of occurrence of all aquatic plant species in the Reservoir. Water lotus (Nelumbo lutea Willd.) was the native species that occurred most often, while alligatorweed (Alternanthera philoxeroides [Mart.] Griseb.) occurred most often with regard to non-natives. A logistic regression model indicated that as species richness increases, the probability of observing a non-native species also increases. Herbicide evaluations implied that the chemical imazapyr provided the largest biomass reduction in alligatorweed over a twelve week period; however, 2,4-D would be the most economical option for long-term control. A pathogen study on alligatorweed revealed the presence of the fungus (Ceratorhiza hydrophilum [Xu, Harrington, Gleason, Et Batzer, Comb., Nov. (Sclerotium hydrophilum [Sacc.]). Future studies should verify the potential or lack thereof of this fungus being a biological control agent on alligatorweed.