Airborne Multispectral Identification of Individual Volunteer and Regrowth Cotton Plants

The boll weevil (Anthonomus grandis grandis) has been eradicated in the U.S. except in the Lower Rio Grande Valley of Texas, but volunteer and regrowth cotton plants create non-managed habitats that can sustain remnant populations of weevils.  Volunteer and regrowth plants are difficult to detect because they often grow individually or in small clusters in rotation crops, fallow fields, and along waterways, highways, railways, and other areas where cotton seed can germinate outside the borders of cotton fields.  Although airborne remote sensing can identify production cotton fields within large areas, new techniques are needed to identify volunteer and regrowth cotton plants in mixed ground cover.  Exhaustive spectral unmixing (ESU) of high-spatial-resolution (0.1 m) airborne multispectral images characterized spectral reflectance of individual volunteer and regrowth cotton plants in corn, milo, soybean, fallow, and bare soil plots.  Results are presented that demonstrate the accuracy of the ESU technique to distinguish volunteer and regrowth cotton plants from bare soil, other crops, and weeds at various stages of crop growth.  Results of this study will help to expedite eradication of the boll weevil from the U.S. by informing eradication program managers where to locate and destroy non-managed cotton plants that serve as potential weevil habitats.