Technical Abstract: Regrowth cotton plants can serve as potential hosts for boll weevils during and beyond the production season. Effective methods for timely areawide detection of these host plants are critically needed to expedite eradication in south Texas. We acquired airborne multispectral images of experimental regrowth cotton fields that contained various developmental stages, sizes, and densities of cotton plants. Airborne multispectral and ground-based hyperspectral reflectance measurements of cotton plants and soil were analyzed using the linear spectral unmixing technique to identify ‘pure’ image pixels of cotton and ‘fuzzy’ image pixels of cotton mixed with soil. The capability to accurately detect cotton plants from medium- or high-resolution images could result in earlier detection and subsequent management of regrowth cotton plants on an areawide basis.