White-barred clearwing

The White-barred clearwing (Synanthedon spheciformis) is a moth belonging to the Sesiidae family within the order Lepidoptera. This species is widely known for its mimicry of Hymenoptera, particularly wasps, which helps the adult moth evade predators. It features clear wings and a distinct black abdomen with characteristic yellow or white banding.

The primary host for this insect is alder (Alnus), though it is occasionally observed on birch trees. It typically attacks the lower trunks and root collars of young or stressed trees. The presence of the pest is often associated with disturbed forest habitats, riparian zones, or areas where the trees have experienced mechanical bark damage.

The life cycle of this species typically spans two years. The flight period of adults occurs from late May through July. Females deposit eggs into crevices in the bark or near wounds. Once hatched, the larvae bore into the bark and cambium layer, where they spend most of their development. They overwinter within the galleries and pupate near the bark surface during their second spring.

The damage caused by the larvae is primarily internal. By feeding on the cambium and xylem, they create extensive galleries that disrupt nutrient transport within the tree. Signs of infestation include the presence of frass (larval droppings) and wood shavings emerging from entry holes. Severe infestations lead to weakened trees, reduced growth rates, and the increased risk of secondary fungal infections or windbreakage.

Effective management strategies focus on integrated pest management (IPM) techniques. Key actions include:

• regular inspection and removal of heavily infested or dead trees before the adult flight period;
• avoiding mechanical damage to tree trunks during logging or maintenance;
• maintaining healthy stand vigor through proper silvicultural practices;
• promoting habitat diversity to support natural predators like parasitic wasps and insectivorous birds.