Temporal Variability of Spectral Reflectance and Estimated Canopy Cover of Cotton Plants Supports Early Detection of Potential Boll Weevil Infestations

Boll weevils may infest cotton plants as soon as squares are produced, but eradication program managers may not be notified that specific cotton fields have been planted until plants are already blooming. Once fields contain fruiting cotton, pheromone traps become ineffective in detecting weevil populations. Timely areawide detection of these potential host plants is critically needed to expedite eradication in south Texas. We acquired a temporal sequence of airborne multispectral images of production cotton fields from planting until first bloom. Multispectral reflectance images of cotton fields were analyzed to calculate canopy cover and characteristic spectral reflectance values, and related to plant height, width, number of nodes, and growth stage. Timely detection of pre-fruiting cotton will aid in mapping, trapping, and subsequent insecticide applications on an areawide basis.