Visualization of damage to Zoysia matrella (L.) Merr. turf infested with white grubs using normalized difference vegetation index obtained via unmanned aerial vehicle observation

White grub is one of the most problematic turfgrass pests in Japan. Because the damage caused by these grubs is difficult to detect at the ground level, a simple method for assessing damage from above the ground is required. Recent studies have developed techniques to evaluate pest‐induced damage to various crops using the normalized difference vegetation index (NDVI), and reports have suggested that grub‐induced damage to turfgrass can be detected. This study aimed to investigate whether NDVI, obtained via an unmanned aerial vehicle (UAV)‐based method, could be used to visualize grub‐induced damage to turfgrass. The experiment was conducted on Zoysia matrella (L.) Merr. where Anomala schönfeldti Ohaus occurs naturally. Three insecticides were applied in June 2023; grubs were counted in September; and NDVI was measured in July, September, and October. The results indicated that grub populations decreased in some insecticide‐treated plots; however, no significant differences in the NDVI were observed. Further research is required to assess grub damage using UAVs, particularly to identify field conditions and refine parameters specific to grub‐induced damage.