Lestes viridis (Vander Linden, 1825)
Fraxinus excelsior, Belgium, prov. Hainaut, Chatelet © Jean-Yves Baugnée
According to most definitions of a gall, oviposition scars like this one are but
“pseudocecida”. They are not specific for a particular host plant species. For example, they have been reported from Fraxinus exelsior, Pinus strobus.
Houard (1908a), Roskam (2019a).