Mulberry longhorn beetle

The mulberry longhorn beetle (Apriona rugicollis) is a significant wood-boring insect belonging to the family Cerambycidae, order Coleoptera. It is a major quarantine pest native to East Asia, known for its destructive impact on various tree species. Its ability to infest healthy, mature trees makes it a critical concern for biosecurity and agriculture.

The host range of this beetle is extensive, including important crops such as mulberry, apple, pear, citrus, fig, and various forest trees like willow and poplar. The larva is a wood-borer that creates extensive galleries inside the trunk and branches, severely compromising the structural integrity and health of the host plant.

The life cycle typically spans 2 to 3 years. The female beetle lays eggs in incisions made in the bark of the host tree. Once hatched, the larvae feed initially in the cambium layer before tunneling deep into the heartwood. After completing their development, they pupate within the wood, and the emerging adults bore out, leaving characteristic round exit holes.

The damage is primarily caused by larval feeding, which disrupts the tree's nutrient and water transport systems. Symptoms include frass (wood dust) accumulation at the base of the tree, yellowing leaves, crown dieback, and branch breakage. Repeated infestations often lead to the death of the tree, causing significant economic losses for fruit producers.

Control strategies prioritize prevention and early detection. Strict phytosanitary measures are essential to prevent the spread of infested nursery stock or timber. In an orchard setting, control methods involve the manual removal and destruction of infested branches or entire trees. Chemical control, such as injecting systemic insecticides directly into larval galleries, may be employed where permissible to manage infestations.