Near Real Time Monitoring of Potato Late Blight Disease Severity using Field Based Hyperspectral Observation
Ramprasad Kundu, Dibyendu Dutta, Manoj Kumar Nanda, Abhisek Chakrabarty
Abstract
Field spectroscopic study was performed using a hand-held Field Spectroradiometer to examine spectral variability between healthy and late blight disease infected potato canopy. The purpose was to select a suitable spectral feature in the visible-near infrared region for late blight disease initiation and severity during winter season. The spectral regions at which significant differences in bio-optical response was observed between healthy and diseased canopy include, 680-730nm (47.84%), 750-900nm (76.14%) and 860-1040nm (68.60%). Correlation study was carried out among different spectral variables, sensitive to PLB disease, and field measured PLB disease severity. Out of all the spectral variables, Red-Edge Normalised Difference Vegetation Index (NDVI705) and Disease Water Stress Index (DWSI) showed significant negative correlation (0.87 and 0.84 at 95% confidence level) and capable to predict the different level of potato late blight disease severity. A remote sensing based novel disease severity method was developed from the above mentioned spectral variables using multi-linear regression model and validated with very high correlation (R2 = 0.883). The scoring method developed could be a good proximal indicator for real-time field monitoring of potato late blight disease.