Submitted to: Imported Fire Ants Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/10/2007
Publication Date: 11/1/2007
Citation: Defauw, S. L., Vogt, J. T. Seasonal Shifts in the Hyperspectral Characterization of Imported Fire Ant (Hymenoptera: Formicidae) Mound Features in Turfgrass. Imported Fire Ants Conference Proceedings. 2007.
Technical Abstract: Safe, expedient, and cost-effective field- to landscape-scale treatments of imported fire ant (IFA) infestations require technological developments that exploit the use of remotely-sensed contrasting features to detect cryptic mounds in heavily-managed turfgrass. Ground-based implementation of hyperspectral techniques in the field-scale quantification and seasonal monitoring of IFA colony distributions is a prerequisite for either designing ground-based sensor arrays or for equipping airborne multispectral digital cameras with appropriate band-pass filters to maximize mound detection for multiple-scale surveys. The objectives of this study are twofold: (1) examine seasonally-acquired spectral reflectance characteristics of ant-affected versus undisturbed turfgrass and soils; and (2) identify bandwidths that enhance the detection of cryptic fire ant mounds in intensively-managed turfgrass areas. Reflectance data (N=22,000 full-range spectra collected August-September 2006), for sparsely-covered ant mounds ('50% vegetation) from Mississippi sites in the North Central Hills and Delta physiographic regions, indicated that mean reflectance values for targets (i.e., bermudagrass, mound soil, and undisturbed bare soil) averaged over 50 nm bandwidths were most distinctive (P<0.001) from each other at 650-700 nm, 1450-1500 nm, and 2000-2050 nm during peak summer season. Reflectance data collected during the Summer-Fall transition displayed shifts in mound feature recognition in the visible (VIS) and near-infrared (NIR) regions, with distinctive bandwidths constrained to just the VIS region ranging from 600-700 nm (P<0.001). The development of new remote sensing monitoring tools, employing seasonally-acquired spectroradiometric data in turf as a model system, will aid site-specific management of fire ant infestations in perennial, warm-season turfgrass settings, help foster sustainable reduction of IFA populations, and benefit a broad base of stakeholders.