Ash weevil

The ash weevil, scientifically known as Stereonychus fraxini, is a member of the Curculionidae family within the order Coleoptera. It is recognized as a specialized pest that exclusively targets ash trees, causing significant concern for foresters and urban arborists across its habitat range.

This insect is strictly oligophagous, meaning its primary food source is the foliage of ash species. Both the adult beetles and their larvae contribute to the defoliation of the host tree, which can lead to weakened tree health if the infestation persists over multiple growing seasons.

The biology of Stereonychus fraxini involves a single generation per year. Adults hibernate throughout the winter months in soil litter or beneath the protective bark of trees. In the spring, they emerge, mate, and deposit eggs directly onto the surface of the young ash leaves.

The damage caused by the ash weevil is characterized by skeletonization. The larvae feed on the leaf tissue while avoiding the larger veins, leaving a lacy pattern behind. This feeding activity reduces the tree's photosynthetic capacity, leading to premature leaf drop and potential stunted growth.

Effective management strategies focus on integrated pest control. Key methods include:

• Monitoring beetle activity during the early spring flush.
• Sanitation practices such as removing leaf litter to reduce overwintering populations.
• Applying targeted insecticides during the larval feeding stage to prevent severe canopy loss.