Mulberry longhorned beetle

Taxonomy: The mulberry longhorned beetle (Apriona plicicollis) is a member of the order Coleoptera and the family Cerambycidae. It is a wood-boring insect that causes significant economic damage to both fruit orchards and ornamental forest plantations.

Host plants: This pest has a wide host range, primarily affecting broad-leaved trees. Major hosts include mulberry (Morus), apple, pear, willow, poplar, elm, and various citrus species. It is considered a dangerous pest in nurseries, where it can cause high mortality rates among young trees.

Biology and life cycle: The life cycle of Apriona plicicollis typically lasts one to two years. Adult females deposit eggs in bark crevices. Upon hatching, the larvae bore into the sapwood and heartwood, creating extensive galleries. These larvae remain inside the wood for most of their life cycle, protecting them from many external environmental factors.

Damage and pest status: The damage is caused by the larval stage, which feeds on the internal tissues of the trunk and branches. Visible symptoms include sawdust-like frass at the base of the tree and circular exit holes on the bark. Heavy infestations lead to branch dieback, crown thinning, and eventual death of the tree, rendering it susceptible to wind breakage.

Protection and control measures: Due to the concealed nature of the larvae, control is challenging:

• Strict quarantine measures to prevent the spread of infested nursery stock.
• Regular inspection and immediate removal of heavily infested trees.
• Application of systemic insecticides to the bark to prevent egg-laying by adults.
• Utilization of biological control agents, such as nematodes, which can be introduced into larval galleries.
• Maintenance of tree vigor through proper irrigation and fertilization.