Hazel aphid

The hazel aphid (Corylobium avellanae) is a member of the Aphididae family, primarily known as a specialist pest of hazelnut trees (Corylus spp.). This insect represents a significant challenge for both commercial nut production and landscape management due to its rapid colonization rate.

The pest typically feeds on young shoots, developing leaves, and buds of the host plant. By sucking sap from these tissues, the aphids cause significant physiological stress, resulting in stunted growth and distorted foliage. In severe cases, the infestation impacts the overall health and vigor of the hazelnut bush.

The life cycle of Corylobium avellanae is closely synchronized with the growth of the hazelnut tree. Overwintering occurs in the egg stage on the bark. As temperatures rise in spring, nymphs hatch and establish colonies that persist throughout the growing season, often utilizing parthenogenesis for rapid population expansion.

The damage caused is twofold: direct extraction of nutrients and the secretion of honeydew. The accumulation of honeydew encourages the growth of sooty mold, a fungus that covers leaf surfaces, further interfering with photosynthesis and reducing the market quality of the harvest.

Management strategies should focus on integrated pest management (IPM) practices. Growers are encouraged to use mechanical removal in small gardens and systemic insecticides in larger orchards when thresholds are exceeded. Maintaining a healthy ecosystem by supporting natural predators like ladybugs is also highly recommended.

• Regular inspection of developing shoots during spring.
• Application of selective systemic insecticides.
• Encouragement of natural aphid predators.
• Avoidance of over-fertilization with nitrogen to reduce succulent growth.