Cottonwood leaf beetle (CLB) is a serious defoliator of cottonwood (Populus spp) in the Unites States and has a significant economic impact on this short-rotation woody crop system. Both adults and larvae damage Populus by feeding on young leaves and shoot, that results in reduced photosynthetic area, height and radial growth reduction, and even mortality. Aerial imaging may assist in rating CLB damage levels and area involved. We have been utilizing a high-resolution DCS CIR 420 digital camera to detect and assess the extent of defoliation in a cottonwood plantation on Togo Island in Mississippi in the green, red, and near infrared (500-810 nm) wavelengths. Digital images were acquired at altitudes of ~152 m, ~305 m and ~610 m on Aug 2 and Oct 19, 2001. Various image enhancement and classification techniques were used along with geostatistical methods to analyze the spectral, spatial and temporal patterns of defoliation by the CLB. Spatial dependent models were used to describe the distribution of reflectance values in a two dimensional space. Heavy feeding by CLB could be detected and assessed, but was less effective in detecting light defoliation. By applying a combination of principal components analysis and spatial analysis with unsupervised /supervised classifications of the remotely sensed images, heavily defoliated trees could be identified in the cottonwood plantation. These methods and results will be elaborated on the poster.
Species 1: Coleoptera Chrysomelidae Chrysomela scripta (cottonwood leaf beetle)
Keywords: cottonwood leaf beetle, digital aerial imagery
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