The light knot grass (Acronicta menyanthidis) is a moth of the family Noctuidae. It is distributed through northern, central and eastern Europe, east to Siberia and the Russian Far East.(For a key to the terms used, see Glossary of entomology terms.)\nThe adults fly at night from May to July . They are attracted to light. 1. \n* The flight season refers to the British Isles. This may vary in other parts of the range.