June 29, 2026 | Indian Phytopathology | Parmar
This study conducted by Anand Agricultural University, India investigated the use of hyperspectral sensing to detect Papaya ringspot virus (PRSV) infection in papaya (Carica papaya L.). PRSV is one of the most destructive diseases affecting papaya production, causing leaf mosaic, chlorosis, ring spots, plant decline, and significant yield losses. Early and accurate disease detection is important for improving disease management and reducing economic losses.
The researchers analyzed leaf reflectance across wavelengths ranging from 350 to 1050 nm to identify spectral changes associated with increasing PRSV severity. Diseased leaves showed higher reflectance in the visible spectrum, particularly around 550 nm, reflecting chlorophyll degradation, and a reduced red-edge slope, indicating impaired chlorophyll function. Reflectance in the near-infrared region also increased as disease severity progressed, suggesting changes in internal leaf structure and water status.
Several vegetation indices, including NDVI, SR, GNDVI, Rre, RVI, and GRVI, declined consistently with increasing disease severity, while the red-edge index increased. Principal component analysis further showed that the red-edge index provided additional information beyond the other vegetation indices.
The findings demonstrate that hyperspectral reflectance measurements can effectively distinguish different levels of PRSV infection and support the development of non-destructive, high-resolution methods for early disease detection and monitoring in papaya production systems.
