USING AIRBORNE VIDEO, GLOBAL POSITIONING SYSTEM, AND GEOGRAPHICAL INFORMATION-SYSTEM TECHNOLOGIES FOR DETECTING AND MAPPING CITRUS BLACKFLYINFESTATIONS

This paper describes the application of airborne video data with globa l positioning system (GPS) and geographical information system (GIS) t echnologies for detecting citrus blackfly (Aleurocanthus woglumi Ashby ) infestations in citrus orchards in the Lower Rio Grande Valley of Te xas. Citrus blackfly infestations could be easily detected on color-in frared (CIR) and black-and-white (B & W) near-infrared (NIR) video ima gery. The blackfly-produced deposits of sooty mold fungus (Capnodium c itri B. & D.) on the trees foliage gave them a distinct gray-black ima ge tonal response. Quantitative data obtained from NIR digitized video images showed that digital values of blackfly-infested trees were sig nificantly lower (p = 0.01) than those from noninfested trees. The GPS latitude-longitude coordinate data of blackfly-infested orchards was entered into a GIS to map infested orchards over a large agricultural area and develop a digital image data base for future reference.