Host plants:
Grasses (Poaceae and probably also Cyperaceae).
Habitat:
Mythimna congrua inhabits at least slightly humid grass stocks, e.g. along rivers and is especially common in coastal swamps. I met the larvae quite abundant in S-France (Camargue), e.g. along ditches in late April 2013 (mature larvae) and in mid-October 2013 (by beating from old grasses, half-grown larvae).
Life cycle:
Mythimna congrua is on the wing in two or three generations between April/May and October. The larva hibernates and can be beaten out of the vegetation when young. Older larvae hide in the vegation near the ground during daytime.
Remarks:
Mythimna congrua occurs in Southern Europe and West Asia. It is locally recorded northward approximately to the French southern Alps and the Italian Po Valley.