Hazel aphid

The hazel aphid (Myzocallis coryli) is a significant insect pest belonging to the Aphididae family, order Hemiptera. It is primarily known for infesting hazelnut trees (Corylus species), causing economic damage in both commercial orchards and ornamental landscapes.

These insects specifically target hazelnut trees, feeding on the phloem sap from the underside of the leaves. While they are small, their ability to reproduce rapidly in spring and summer allows them to form massive colonies that drain plant resources and weaken the host tree significantly.

The biological cycle starts with overwintering eggs laid on the bark of young shoots. In early spring, nymphs hatch and transition into wingless fundatrices. Throughout the season, several generations occur, with winged forms appearing later to facilitate the colonization of healthy neighboring trees.

Damage is characterized by leaf curling, chlorosis, and premature senescence of the foliage. The aphid excretes honeydew, a sticky substance that promotes the growth of sooty mold. This layer of fungus hinders photosynthesis, which ultimately leads to reduced nut quality and stunted growth of the tree.

Integrated Pest Management (IPM) is the best approach for long-term control. Effective strategies include:

• Early season monitoring to detect the first aphid colonies.
• Application of systemic insecticides during peak infestation periods.
• Conservation of natural predators like lacewings, lady beetles, and hoverflies.
• Pruning to improve air circulation and reduce habitats for aphids.