European Corn-borer Ostrinia nubilalis
Wingspan 26-30 mm.
A rare migrant before the 1930's, this species then began to colonise the area around London and the south-east, and has spread to several other areas since.
The males are darker than the females, and usually slightly smaller.
The single generation flies in June and July, and the main foodplant in Britain is mugwort (Artemisia vulgaris), although abroad it is often a pest on maize crops.