Hazelnut weevil

Systematic position: The hazelnut weevil (Curculio neocorylus) belongs to the order Coleoptera and the family Curculionidae. It is a specialized pest known for its long rostrum, which allows the female to penetrate the hard outer shell of the developing nut to deposit eggs.

Host plants: The primary hosts for this species include common hazel (Corylus avellana) and various cultivated hazelnut varieties. It acts as a major limiting factor in commercial nut production, often leading to severe quality loss.

Biology and life cycle: The adult weevils emerge from the soil in late spring and early summer. After mating, females bore holes into young nuts to lay their eggs. The larva develops entirely inside the nut, feeding on the developing kernel. Once mature, the larva bores a circular hole through the shell, exits the nut, and drops to the ground to overwinter in the soil.

Damage and economic importance: The damage is primarily caused by the larvae, which consume the kernel, rendering the nuts empty or infested with frass. Infested nuts are often categorized as cull and are unsuitable for market, significantly reducing the marketable yield and overall profitability of the orchard.

Management strategies: Controlling Curculio neocorylus requires an integrated pest management (IPM) approach:

• Sanitation through the frequent removal and destruction of fallen infested nuts.
• Cultivation of the soil under the tree canopy to disrupt the pupation process and kill overwintering larvae.
• Timing insecticide applications during the adult emergence phase, before egg-laying occurs.
• Monitoring adult activity using specialized traps to ensure timely intervention.