Monitoring Cotton Root Rot Progression within and Across Growing Seasons Using Remote Sensing

Cotton root rot, caused by the soilborne fungus Phymatotrichopsis omnivore Shear (Duggar), is one of the most destructive plant diseases occurring throughout the southwestern U.S. More recently, a fungicide, flutriafol, has been evaluated in Texas and was found to have the potential for controlling this disease. It is necessary to identify infected areas within the field so that variable rate technology can be used to apply the fungicide only to infected areas for more effective and economical control. The objectives of this study were to use airborne multispectral imagery for detecting and monitoring the expansion of root rot infection in cotton fields within and across growing seasons. Two dozen cotton fields near Edroy and San Angelo, Texas were selected for this study. Airborne multispectral digital imagery with blue, green, red and near-infrared bands was taken from these fields multiple times during the growing seasons in 2009, 2010, and 2011. In this paper, four images taken from a field near San Angelo in 2011 was used to illustrate the progression of cotton root rot within the growing season, and two images taken from a field near Edroy in 2001 and 2011, respectively, were used to demonstrate the consistency and change of this fungus over a 10-year interval. The results from this study will be useful for the understanding of the progression of the disease and for the development of site-specific treatment plans for the disease.