Evaluation of light aircraft remote sensing techniques for the detection and quantification of cane rust

This report describes a test of small format (70mm) color infrared aerial photography in locating and evaluating the severity of sugar cane rust in a test site northeast of Santo Domingo. Color infrared photographs were taken at three different altitudes with a Hasselblad 500 EL/M camera with an 80mm focal length lens and were interpreted using a five-level classification system to estimate infestation levels based on stage of growth and tonal rendition; a similar system classified the ground truth observations made in the test area. The highest correlation (89%) between interpreted infestation levels and ground truth data was obtained for the largest scale imagery (approximately 1: 1,000); correlations ranged from 91% to 96% for all combinations. At the same time, multi-band photographs were taken using a NAC model MB-470 camera. The study indicates that both color infrared and multi-band light aircraft remote sensing techniques can provide reliable information on the status and geogaphic extent of infested sugar cane crops.