The cotton aphid has become a consistent and abundant pest of cotton in Georgia, but the extent of economic damage inflicted by this pest is unclear. This study was undertaken to evaluate the impact of natural enemies on cotton aphid populations, and to assess the impact of aphids on cotton yields. Four treatments were evaluated: (1) an untreated control, (2) a benomyl (fungicide) treatment to reduce the activity of the entomopathogenic fungus Neozygites fresenii, (3) an imidacloprid treatment when aphids were present on >50% of the plants, and (4) an imidacloprid treatment when aphids were present on >>50% of the plants, and natural enemies were present. The studies were conducted in a commercial cotton field with 1-acre plots and four replicates of each treatment (total of 16 acres). Cotton aphid populations were low until late June, when numbers increased, triggering imidacloprid treatments in early July. Aphid populations declined rapidly in the imidacloprid plots, but declined nearly as rapidly in all other plots as a fungal epizootic decimated the aphid populations. Other natural enemies appeared to have less impact, although a few other natural enemy species were found in the field (e.g., Scymnus spp. and other coccinellids). Seed cotton yields were higher in fungicide treated plots, but no significant differences were observed among any of the remaining plots.