D3437: Utilizing remote sensing technologies to monitor and quantify spider mite (Tetranychus spp.) damage California almonds (Prunus dulcis)

Spider mites (Tetranychus spp.) are known to infest almond (Prunus dulcis) orchards throughout the summer months in California’s Central Valley. They feed on the intercellular contents of leaves using piercing-sucking mouthparts causing stippling, necrosis, defoliation and yield reductions in the years following severe damage. While almond acreage in the Central Valley has nearly doubled over the past decade, spider mite monitoring methods remain largely unchanged, emphasizing time consuming in situ counts under a hand lens. Cameras mounted to Unmanned Aerial Vehicles (UAVs) have generated special interest among pest management professionals, as their high spatial resolution allows for the rapid detection of arthropod damage over extensive landscapes. Here we demonstrate the utilization of RGB (Red Green Blue), Multispectral, Thermal and LiDAR sensors equipped to aerial and ground-based platforms to detect sider mite damage in almond blocks under differential spider mite feeding pressure. Correlation and regression analysis between drone imagery and ground truthing metrics, were conducted to link relevant ground truthing metrics with drone imagery. Preliminary analysis reveals that low resolution RGB sensors are insufficient in the detection of spider mite damage in almonds, however, analysis of multispectral imagery is to follow. Considering these conditions, a monitoring protocol using drones equipped with sensors capable of detecting spider mite damage could provide a more efficient spider mite monitoring method. However, this approach will likely require sophisticated cameras capable of detecting spectra beyond the visual bandwidths.