Effective gap-based exclusion netting to prevent oviposition by the red-necked longhorn beetle Aromia bungii on ornamental trees

The red-necked longhorn beetle, Aromia bungii (Coleoptera: Cerambycidae), is a wood-boring pest of ornamental cherry trees in the Rosaceae family. This study evaluates the effectiveness of a preventive measure using fine-mesh netting in preventing A. bungii from oviposition on host cherry trees. Aromia bungii typically oviposits in cracks and crevices of host tree bark using its elongated ovipositor, leading to higher infestations on the lower trunk where there are abundant rough barks suitable for the beetle oviposition. Therefore, we assessed the effectiveness of netting with a gap that exceeded the reach of the A. bungii ovipositor from the tree surface. This evaluation involved laboratory experiments using cut branches and field experiments using lower trunks from standing trees. In the field, we determined the distribution of A. bungii body sizes and estimated the maximum ovipositor length based on their proportional relationship. This led to the establishment of a 10 mm gap for the test net, featuring a 0.4 mm mesh. Both laboratory and field experiments confirmed that the 0.4 mm mesh net with the specified gap effectively prevented A. bungii oviposition in netted areas. Field experiments also suggested a potential shift in oviposition sites from netted (lower) to un-netted (upper) areas in trees with nets, considering results from trees without nets. Although various measures, such as insecticide spraying, are necessary to safeguard areas without nets, our netting method can serve as a fundamental component of integrated pest management against A. bungii.