How can drones be used to detect tree of heaven to monitor and manage spotted lanternflies?

The spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), is an invasive pest, and its preferred host plant is the tree of heaven (Ailanthus altissima), a rampant invasive tree species. Currently, no effective trapping methods of L. delicatula are available, and thus pest managers solely rely on ground surveys to detect tree of heaven for L. delicatula management. The objective of this study was to detect, map, and validate the presence of the tree of heaven using a drone for the monitoring and management of L. delicatula. Aerial surveys were conducted using drones equipped with optical sensors throughout the year. Aerial images obtained from drones were stitched to generate a composite image, which was used to detect trees of heaven. Optimal drone flight altitudes, accuracy of detection and the spatial distribution of tree of heaven were determined. The results of this study showed that the tree of heaven could be identified using an RGB sensor at a flight altitude of < 25 m above the tree canopy with seed clusters in winter and seed pods in summer. The accuracy of drone detection of tree of heaven was 87.4%. Thermal sensors detected heat signatures, as the temperature of seedpods (0.37 ± 0.3 °C) was lower than that of branches (3.06 ± 0.5 °C) on cold sunny days. These results indicate that the use of drones with optical sensors can be a safe, real-time, and efficient tool for tree of heaven detection for monitoring and developing effective strategies for L. delicatula management.