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

Author
item Everitt, James
item Escobar, David
item Summy, Kenneth
item Alaniz, Mario
item Davis, Michael

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Improved methods are needed to detect and map insect infestations in agricultural areas. Airborne video imagery was evaluated for detecting whitefly infestations in cotton fields and harvester ant infestations in pasture lands in the Lower Rio Grande Valley of Texas. Video data was integrated with global positioning system (GPS) and geographical information system (GIS) technologies. Whitefly infestations could be detected in color-infrared and black-and-white (B&W) near-infrared video imagery based on the presence of whitefly-produced deposits of sooty mold fungus on the cotton foliage. Harvester ant infestation could be readily distinguished in B&W red video imagery based on their circular shape. The integration of the GPS with the video imagery permitted the latitude/ longitude coordinates of whitefly and harvester ant infestations to be printed on each image. The GPS coordinates were entered into a GIS to map whitefly and harvester ant infestations in cotton fields and pasture lands respectively. These technologies enable agricultural specialists to develop regional maps depicting where insect infestations occur over large agricultural areas.

Technical Abstract: This paper describes the application of airborne videography with global positioning system (GPS) and geographic information system (GIS) technologies for detecting and mapping whitefly infestations in cotton and harvester ant infestations in pasture land in the Lower Rio Grande Valley of Texas. Plant canopy reflectance measurements made on cotton plants with hno whitefly-produced deposits of sooty mold fungus, those with low-moderat levels, and those with high levels showed that plants with low-moderate and high levels of sooty mold generally had lower visible and near-infrared reflectance than plants with no sooty mold. Whitefly infestations could be detected in color-infrared and black-and-white near-infrared video imagery based on the presence of whitefly-produced deposits of sooty mold fungus on the cotton foliage, which gave the cotton a dull magenta to gray-black image tonal response. Harvester ant infestations could be easily distinguished in black-and-white red video imagery where the ant mounds ha a distinct light gray to white image response. The integration of the GPS with the video imagery permitted latitude-longitude coordinates of whitefly and harvester ant infestations to be recorded on each image. The GPS latitude-longitude coordinates were entered into a GIS to map whitefly and harvester ant infestations in cotton fields and pasture lands, respectively.