Poplar clearwing

Systematic position. The poplar clearwing (Paranthrene dolii) belongs to the order Lepidoptera and the family Sesiidae. It is recognized as a significant stem-boring pest that poses a persistent threat to various deciduous tree species, often remaining hidden until significant structural damage has occurred.

Host plants and damage. The primary hosts include various species of poplar (Populus) and willow (Salix). The larvae tunnel into the wood of trunks and branches, disrupting the flow of sap, weakening the tree structure, and causing significant growth reduction. Infested branches often break easily, and severely attacked trees may eventually die if not properly managed.

Biology and life cycle. Adults exhibit Batesian mimicry, resembling wasps to avoid predation. The flight period of the adults occurs during the summer months. Females lay their eggs in bark crevices or near physical wounds on the trunk. Upon hatching, the larvae bore directly into the wood, where they undergo development, feeding for one or two years before pupating within the galleries.

Damage symptoms. The most common indicators of an infestation include the presence of larval exit holes on the bark and accumulations of frass (boring dust) at the base of the tree or at the site of entry. Furthermore, sap weeping or resin flow from the bark indicates deeper larval damage, often making the tree susceptible to secondary fungal infections.

Control measures. Integrated pest management involves proper silvicultural practices, such as removing and destroying heavily infested branches. Applying insecticides to the trunk during the adult flight period can reduce egg-laying success. Additionally, using pheromone traps is recommended for monitoring populations and timing control interventions to ensure the health and longevity of tree plantings.