Agrilus biguttatus (Fabricius, 1776)
long, zigzagging gallery under the bark, mostly in horizontal directions. This interrupts the sap stream and may kill the tree. According to Buhr sometimes strong callus formation occurs, resembling galling.
during the last decennia the species has strongy increased in abundance, and plays a significant role in oak dieback. Its presence can be ascertained by the characteristic exit holes in the bark, having the shape of a capital “D”.
Buhr (1965a), Moraal & Hilszczanski (2000a).