Hyperspectral Imaging for Determining Reflection Variables in Chilli Leaves Infested with Green Peach Aphid

Atshan, L.A., H.A. Ibrahim, K.J. Abdulrazzaq and K.A. Atshan. 2024. Hyperspectral Imaging for Determining Reflection Variables in Chilli Leaves Infested with Green Peach Aphid. Arab Journal of Plant Protection, 42(3): 299-305. https://doi.org/10.22268/AJPP-001256 Aphid infestations cause a physiological response detectable by a remote leaf reflectance sensor. Changes in the spectral signature of specific wave bands, measured with hyperspectral imagery (HI), may also relate to the absence, presence and/or level of infestation of aphids. Aphids cause significant damage to crops and yields in the field as well as in greenhouses. Green peach aphid, Myzus persicae (Sulzer) destroy chloroplast cells; this damage can be spectrally detected in the reflectance of the visible and near-infrared (NIR) regions. The spectral curve showed that the aphid-infested chili leaves reflectance in the NIR, decreased in time with the increase of aphid population. Although the aphid’s activity occurred on the leaves underside, their damage can be spectrally detected by reflection data from the upper side. Early aphid damage was identified in limited areas of chili leaf and this damage showed to be the only harm inflicted on the plant, also proven by the HI data obtained. Surface reflectance (%) from un-infested chili was lower in the visible and higher in the NIR light 90A spectrum when compared with aphids-infested chili. The overall classification accuracies of 89% for damage detection were achieved. These results indicated that HI can be effectively used to accurately detect and quantify aphid infestation in chili for site-specific aphid management. It can be potentially applied for limited areas as well as fields as an early detection tool for aphid management. This study aimed to spectrally explore the ability to assess the level of aphids damage in a limited area grown with the chili crop. Keywords: Hyperspectral imagery, aphids, chilli pepper, near-infrared