Adaina microdactyla - Exit hole on Eupatorium cannabinum

The stems of Hemp-agrimony (Eupatorium cannabinum) can be locally swollen, especially on the junctions with the leafs, due to breeding chambers of the Plume moth Adaina microdactyla in the stem. After the moth emerges the situation is given away more clearly by the exit hole of the moth. The development of the moth seems to have little or no negative impact on the plant.