The effects of natural enemies on cotton aphid population density was monitored using four cage types to exclude or include predators and/or parasitoids. The treatments examined were total exclusion, partial exclusion, open cage, and uncaged control. Aphid densities were significantly higher in the total exclusion treatment than in any other treatment, indicating the importance of natural enemies in the suppression of cotton aphids. The small coccinellid, Scymnus spp., appears to have been the most important predator of cotton aphids throughout the study. The results of the current study indicate that aphids are initially suppressed by the entomopathogenic fungus, Neozygites fresenii, and are kept at low levels thereafter by parasitoids and predators, most notably Scymnus spp., preventing further outbreak.