Rotylenchulus reniformis (the reniform nematode) is considered to be the major nematode problem of Upland cotton (Gossypium hirisutum) in Alabama and other Southern States. A rotation system of cotton to corn is often utilized because corn is a non-host to the reniform and has the ability to reduce populations. Many of the weed problems between the two crops are similar. Recently, growers have begun to observe stable populations of the reniform nematode in correlation with cotton-corn rotation. It has been proposed that the noxious weed plants associated with the rotation scheme may be acting as a host for the reniform nematode, therefore sustaining populations. Selected weed species were screened for host status in the greenhouse. Corn and individual weed species populations growing together were evaluated in a microplot field study to quantify reniform population status. A field trial was conducted in a naturally infested reniform cotton field in Huxford, AL, where corn was grown under different herbicide regimes to simulate various weed conditions in order to determine if the noxious weed plants associated with the cotton-corn rotation system may serve as hosts to the reniform nematode. Greenhouse trials indicate that of the thirty-nine species tested, the majority of dicotyledonous noxious weed species serve as host to the reniform nematode while the monocotyledonous species do not. In microplot studies, corn growing in combination with individual weed species of Coffeesenna, Common Ragweed, Prickly Sida, Mixed Morningglory, and Sicklepod increase reniform nematode populations. Noxious weed species in field plots without herbicide applications have proven to increase reniform nematode populations as compared to the weed-free treatments. Noxious weed plants associated with the cotton-corn rotation system may be the cause of reniform nematode population's sustainability.