Potato spectral response to biotic and mechanical defoliation, and chemical application using RapidSCAN

Sustainable potato protection requires integrated pest management, including reliable pest detection and quick response, especially in precision agriculture where conventional scouting is costly and laborious. We quantified the relationship between potato reflectance and Colorado potato beetle (CPB) damage and compared reflectance on plants subjected to conventional (imidacloprid) intervention with untreated control plants. Potted potato plants were manipulated to create three defoliation groups to assess plants’ spectral reflectance indices [Normalized Difference Vegetation Index (NDVI) and Normalized Difference Red Edge (NDRE) using RapidSCAN CS-45TM], percentage plant and leaf damage for four days. Elsewhere, reflectance and biomass of plants grown from imidacloprid and water (control) -treated tubers were assessed. Results showed that NDVI values dropped slightly on mechanically defoliated plants but severely for CPB defoliated plants, noticeable a day later from handheld optical sensor, and worsened as defoliation increased. The application of imidacloprid to potato seeds did not substantially affect reflectance but significantly boosted growth as opposed to yield, which was higher for the control, suggesting differential resource allocation: what the former allocates to vegetative growth, the latter to tubers. Given their similar aggregate biomass, they both had similar finite resources, but differential use patterns, with no effects on spectral reflectance. These showcase quick detection of CPB’s stressed potato for early response and stress mitigations, and the absence of imidacloprid-linked changes in reflectance. In sum, the device encourages smart and sustainable farming through early stress detection and response to reduce pest scouting time and management cost as integral parts of pest management.