Using WorldView-2 bands and indices to predict bronze bug (Thaumastocoris peregrinus) damage in plantation forests

Abstract

Thaumastocoris peregrinus is an insect that causes significant damage to Eucalyptus plantations internationally. This bug inhibits the photosynthetic ability of the tree, resulting in stunted growth and even death of severely infested trees. This study uses high spatial resolution satellite imagery (WorldView-2 sensor data), with unique band settings for the prediction of T. peregrinus damage in plantation forests using partial least squares (PLS) regression. The PLS models developed from the WorldView-2 sensor bands and indices were inverted to map the severity of the damage caused by the pest. The WorldView-2 sensor bands and indices predicted T. peregrinus damage with an R ² value of 0.65 and a root mean square error (RMSE) of 3.62% on an independent test data set. The red-edge and near-infrared bands of the WorldView-2 sensor and pigment-specific indices and red-edge indices were identified as significant bands by variable importance scores for the prediction of T. peregrinus damage. This study demonstrates the potential of WorldView-2 sensor data in successfully predicting T. peregrinus damage using PLS regression and identifies important spectral variables for the prediction of forest damage in plantation forests.

Acknowledgements

The authors thank Muhammad Sheik Oumar and Thato for helping with the field data collection and are grateful to DigitalGlobe for providing them the WorldView-2 imagery. The funding for this research was provided by the National Research Foundation and the University of KwaZulu-Natal.