Green walnut longhorn beetle

Systematic position. The green walnut longhorn beetle (Chloridolum sieversi) belongs to the order Coleoptera and the family Cerambycidae. As a specialized wood-boring insect, it presents a significant threat to the cultivation of nut-bearing trees in various geographical regions.

Host plants. The primary host for this pest is the common walnut (Juglans regia). The beetle exhibits a strong preference for healthy and stressed walnut trees alike, making it a challenging pest in both commercial plantations and smaller orchards where tree health management is vital.

Biology and life cycle. The life cycle of the beetle is deeply integrated into the wood of the host tree. Adult beetles are typically active during the summer, searching for mates and suitable oviposition sites in the bark. Upon hatching, the larvae tunnel into the cambium and inner wood, feeding for several years before pupating and eventually emerging as adults.

Damage and harmfulness. The larvae cause the most significant damage by disrupting the tree's vascular system, which hinders the flow of water and nutrients. This leads to the progressive dieback of branches, wilting foliage, and overall tree decline. Infested trees often show distinct holes in the bark and mounds of frass, rendering them susceptible to secondary pests and fungal infections.

Protection measures. Managing this pest requires an integrated approach to maintain orchard vitality. Essential practices include:

• Regular monitoring for signs of infestation and frass.
• Prompt removal and destruction of infested wood to reduce larval populations.
• Application of targeted insecticides during the adult emergence period.
• Maintaining optimal tree vigor through balanced fertilization and irrigation to improve resistance.