Alternating longhorn beetle

The Alternating longhorn beetle (Dorcaschema alternatum) is a wood-boring insect belonging to the Cerambycidae family within the order Coleoptera. This species is widely recognized as a specialized pest that targets various host trees, primarily focusing its life cycle on members of the Moraceae family.

The primary hosts for this beetle are mulberry trees (Morus). The damage is bifurcated: adult beetles feed on the bark of tender twigs and leaves, while the larvae are internal wood feeders. This dual attack strategy allows the pest to inflict stress on both the canopy and the structural integrity of the tree's trunk.

The biological cycle of this longhorn beetle involves the female laying eggs in crevices or wounds in the tree bark. Upon hatching, the larvae tunnel into the xylem and phloem, creating galleries that disrupt water and nutrient transport. These galleries serve as a focal point for further degradation and can lead to structural instability of the branches.

The damage caused by Dorcaschema alternatum includes wilting of foliage, branch dieback, and overall decline in tree health. In nurseries and orchards, this pest can significantly reduce the vitality of young stock, leading to stunted growth and economic losses due to the premature death of infested trees.

Management and control strategies are essential to mitigate the impact of this pest:

• Sanitary pruning of infested wood to remove larvae before they emerge.
• Implementation of chemical controls during the peak adult activity period.
• Improving tree vigor through proper fertilization and irrigation.
• Using physical barriers on trunks to prevent egg-laying by adult females.