Similar to it's larger cousin, the Large Yellow Underwing, the Lesser Yellow Underwing is generally smaller, with a wingspan of 38-45mm, and the wingspan is thicker at the edge of the forewing. The forewing colour can be pale or dark grey, to reddish brown. The hindwing is yellow/orange, and has a thin black border and a dark crescent.
This species is common throughout Britain, and often comes to light. This species is found in a wide variety of habitats.
The Lesser Yellow Underwing flies from June-October.
The larvea feed on docks, plantains, foxgloves, birch and other species.