Fusion of Medium- and High-Resolution Remote Images for the Detection of Stress Levels Associated with Citrus Sooty Mould

Citrus sooty mould caused by <i>Capnodium</i> spp. alters the quality of fruits on the tree and affects their productivity. Past laboratory and hand-held spectrometry tests have concluded that sooty mould exhibits a typical spectral response in the near-infrared spectrum region. For this...

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Main Authors: Enrique Moltó, Marcela Pereira-Sandoval, Héctor Izquierdo-Sanz, Sergio Morell-Monzó
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Agronomy
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Online Access:https://www.mdpi.com/2073-4395/15/6/1342
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author Enrique Moltó
Marcela Pereira-Sandoval
Héctor Izquierdo-Sanz
Sergio Morell-Monzó
author_facet Enrique Moltó
Marcela Pereira-Sandoval
Héctor Izquierdo-Sanz
Sergio Morell-Monzó
author_sort Enrique Moltó
collection DOAJ
description Citrus sooty mould caused by <i>Capnodium</i> spp. alters the quality of fruits on the tree and affects their productivity. Past laboratory and hand-held spectrometry tests have concluded that sooty mould exhibits a typical spectral response in the near-infrared spectrum region. For this reason, this study aims at developing an automatic method for remote sensing of this disease, combining 10 m spatial resolution Sentinel-2 satellite images and 0.25 m spatial resolution orthophotos to identify sooty mould infestation levels in small orchards, common in Mediterranean conditions. Citrus orchards of the Comunitat Valenciana region (Spain) underwent field inspection in 2022 during two months of minimum (August) and maximum (October) infestation. The inspectors categorised their observations according to three levels of infestation in three representative positions of each orchard. Two synthetic images condensing the monthly information were generated for both periods. A filtering algorithm was created, based on high-resolution images, to select informative pixels in the lower resolution images. The data were used to evaluate the performance of a Random Forest classifier in predicting intensity levels through cross-validation. Combining the information from medium- and high-resolution images improved the overall accuracy from 0.75 to 0.80, with mean producer’s accuracies of above 0.65 and mean user’s accuracies of above 0.78. Bowley–Yule skewness coefficients were +0.50 for the overall accuracy and +0.28 for the kappa index.
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institution Kabale University
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publishDate 2025-05-01
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series Agronomy
spelling doaj-art-9abcf8def4294f1b96dcea2f4270586c2025-08-20T03:30:24ZengMDPI AGAgronomy2073-43952025-05-01156134210.3390/agronomy15061342Fusion of Medium- and High-Resolution Remote Images for the Detection of Stress Levels Associated with Citrus Sooty MouldEnrique Moltó0Marcela Pereira-Sandoval1Héctor Izquierdo-Sanz2Sergio Morell-Monzó3Instituto Valenciano de Investigaciones Agrarias (IVIA), Centro de Agroingeniería, Carretera CV-315, Km 10.7, 46113 Moncada, SpainInstituto Valenciano de Investigaciones Agrarias (IVIA), Centro de Agroingeniería, Carretera CV-315, Km 10.7, 46113 Moncada, SpainInstituto Valenciano de Investigaciones Agrarias (IVIA), Centro de Agroingeniería, Carretera CV-315, Km 10.7, 46113 Moncada, SpainEscuela Politécnica Superior de Gandía, Universitat Politècnica de València (Polytechnical University of Valencia), 46730 Gandía, SpainCitrus sooty mould caused by <i>Capnodium</i> spp. alters the quality of fruits on the tree and affects their productivity. Past laboratory and hand-held spectrometry tests have concluded that sooty mould exhibits a typical spectral response in the near-infrared spectrum region. For this reason, this study aims at developing an automatic method for remote sensing of this disease, combining 10 m spatial resolution Sentinel-2 satellite images and 0.25 m spatial resolution orthophotos to identify sooty mould infestation levels in small orchards, common in Mediterranean conditions. Citrus orchards of the Comunitat Valenciana region (Spain) underwent field inspection in 2022 during two months of minimum (August) and maximum (October) infestation. The inspectors categorised their observations according to three levels of infestation in three representative positions of each orchard. Two synthetic images condensing the monthly information were generated for both periods. A filtering algorithm was created, based on high-resolution images, to select informative pixels in the lower resolution images. The data were used to evaluate the performance of a Random Forest classifier in predicting intensity levels through cross-validation. Combining the information from medium- and high-resolution images improved the overall accuracy from 0.75 to 0.80, with mean producer’s accuracies of above 0.65 and mean user’s accuracies of above 0.78. Bowley–Yule skewness coefficients were +0.50 for the overall accuracy and +0.28 for the kappa index.https://www.mdpi.com/2073-4395/15/6/1342plant protectionSentinel 2orthophotosspectral indicesmultifold cross-validation
spellingShingle Enrique Moltó
Marcela Pereira-Sandoval
Héctor Izquierdo-Sanz
Sergio Morell-Monzó
Fusion of Medium- and High-Resolution Remote Images for the Detection of Stress Levels Associated with Citrus Sooty Mould
Agronomy
plant protection
Sentinel 2
orthophotos
spectral indices
multifold cross-validation
title Fusion of Medium- and High-Resolution Remote Images for the Detection of Stress Levels Associated with Citrus Sooty Mould
title_full Fusion of Medium- and High-Resolution Remote Images for the Detection of Stress Levels Associated with Citrus Sooty Mould
title_fullStr Fusion of Medium- and High-Resolution Remote Images for the Detection of Stress Levels Associated with Citrus Sooty Mould
title_full_unstemmed Fusion of Medium- and High-Resolution Remote Images for the Detection of Stress Levels Associated with Citrus Sooty Mould
title_short Fusion of Medium- and High-Resolution Remote Images for the Detection of Stress Levels Associated with Citrus Sooty Mould
title_sort fusion of medium and high resolution remote images for the detection of stress levels associated with citrus sooty mould
topic plant protection
Sentinel 2
orthophotos
spectral indices
multifold cross-validation
url https://www.mdpi.com/2073-4395/15/6/1342
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