Hazel spider mite

Systematic position: The hazel spider mite (Eotetranychus coryli) belongs to the order Acariformes and the family Tetranychidae. It is a microscopic herbivorous mite that primarily inhabits the underside of host leaves, feeding on plant cell contents and impacting overall plant vitality.

Host plants: This mite is commonly found on hazel (Corylus avellana) and various related species. However, it is also known to infest a range of deciduous fruit trees such as apples, pears, and plums, making it a generalist pest in diverse orchard environments.

Biology and life cycle: The mites overwinter as fertilized females in bark crevices or among debris. As temperatures rise in spring, they colonize emerging leaves. The life cycle consists of several generations per year, with development highly accelerated by hot and dry weather conditions, which often leads to rapid population outbreaks.

Damage and economic significance: Feeding activity causes characteristic stippling on the leaves, which eventually turn pale, yellow, and wither prematurely. Heavy infestations cause significant stress to the host plant, reducing nutrient storage and resulting in substantial yield losses, particularly in commercial hazelnut orchards.

Control measures: Integrated Pest Management (IPM) is essential. Cultural practices such as maintaining tree health and proper orchard sanitation help reduce wintering sites. When economic thresholds are exceeded, targeted applications of acaricides should be used. It is crucial to rotate chemical classes to prevent the development of mite resistance.