Last modified: Feb. 22, 2021, 4:19 p.m.
Eggs are laid inside Betula twigs, usually at a node, and the larva feeds and eventually pupates inside a thick white cocoon inside the gall as well, where it hibernates.
The moths are active in the afternoon sunshine. They come to light in small numbers.
The adults fly in May and June.
The larvae live in a gall on Betula.