Description: The Hornet moth is a perforating Lepidoptera, 35-45 mm in size that mainly affects the cottonwood, but can also attack other trees such as willows, birches and alders.
Number of annual generations: this species needs at least two years to complete its biological cycle.
Damage: the larvae make descending galleries at the base of the trunk and roots. These galleries break the conductive tissues affecting the circulation of the sap and weakening the tree. In many cases the affected areas break in the wind. The wood of the tree may also be affected.