A survey was conducted to compare cotton aphid, Aphis gossypii, populations in that portion of Mississippi not involved in boll weevil eradication to populations in the Hill region, which had initiated eradication efforts in late summer of 1997 and was involved in the first full season of eradication in 1998. Aphid populations were distinctly higher inside the eradication area, peaking at levels approximately 5-fold higher than in the Delta and occurring approximately two weeks earlier. All nine survey fields in the Hill region exceeded average aphid populations of 100 per leaf or were treated with an aphicide before aphid populations reached this level. Only one of seven survey fields in the Delta region exceeded 100 aphids per leaf. This flaring of aphid populations in the eradication area is attributed to the destruction of beneficial insects as a result of applications of ULV malathion applied to control boll weevils. An epizootic of the fungal disease Neozygites fresenii, ultimately provided control of aphid populations in both regions, but development of this epizootic occurred approximately one week later in the Delta than in the Hill region. Yield losses to aphids flared as a result of eradication efforts are difficult to estimate, but were likely offset in whole or in part by reductions in losses to boll weevils.