USING SPATIAL INFORMATION TECHNOLOGIES FOR DETECTING AND MAPPING WHITEFLY AND HARVESTER ANT INFESTATIONS IN SOUTH TEXAS

This paper describes the application of airborne videography with glob al positioning system (GPS) and geographic information system (GIS) te chnologies for detecting and mapping whitefly (Bernesia sp.) infestati ons in cotton (Gossypium hirsutum L.) and harvester ant (Pogonomyrmex barbatus F. Smith) infestations in pasture lands in the Lower Rio Gran de Valley of Texas. Plant canopy reflectance measurements made on cott on plants with no whitefly-produced deposits of sooty mold fungus (Cap nodium sp.), those with low-moderate levels, and those with high level s showed that plants with low-moderate and high levels of sooty mold g enerally had lower visible and near-infrared reflectance than plants w ith no sooty mold. Whitefly infestations could be detected in color-in frared and black-and-white near-infrared video imagery based on the pr esence of whitefly-produced deposits of sooty mold fungus on the cotto n foliage, which gave the cotton a dull magenta to gray-black image to nal response. Harvester ant infestations could be easily distinguished in black-and-white red video imagery where the ant mounds had a disti nct light gray to white image response. The integration of the GPS wit h the video imagery permitted latitude-longitude coordinates of whitef ly and harvester ant infestations to be recorded on each image. The GP S latitude-longitude coordinates were entered into a GIS to map whitef ly and harvester ant infestations in cotton fields and pasturelands, r espectively.