Water stress detection as an indicator of red palm weevil attack using worldview-3 data

This study focuses for the first time on the water stress detection and discrimination among different stages of red palm weevil (RPW) stress-attacks using water stress indices (WSI) and linear and second order polynomial statistical analysis. Different WSI were assessed using new technology Worldview-3 (WV-3) simulated data. Based on field identification, five palm tree classes were considered: dead, severely attacked, attacked-untreated, attacked-treated; and healthy trees. Spectral measurements were acquired over each sample using Analytical Spectral Devices (ASD). They were resampled and convolved using WV-3 spectral response profiles and the Canadian radiative transfer code (CAM5S). Results showed that the indices NDWI, SRWI, SIWSI-1, SIWSI-2 and NDII are sensitive to palm trees water agitation caused by RPW attacks. They discriminated among the considered classes with excellent R
²
values (≈ 95%) using second order polynomial function (p < 0.05). Nevertheless, they express the water content dynamic range about only 10% to 55%. New Palm Tree Water Stress Index (PTWSI) were proposed using WV-3 SWIR bands. They differentiated among the considered classes with R
²
of 90%, and enhanced significantly water content dynamic range for a maximum about 90% or 100%. According to these first results, it was concluded that remote sensing science using WV-3 data is a promising alternative for RPW detection based on WSI.