The Mythimna unipuncta
wingspan is 35 - 47 mm. The forewing is tan, and often tinged with orange and lightly speckled with black. The postmedian line is a series of small widely-spaced black dots. The discal spot is white. A black-shaded line slants inward from the apex. The hindwing is grayish-brown with a tan fringe (Powell and Opler, 2009).
The Mythimna unipuncta larvae has a pale brown head with green tinge and mottled with dark brown. The larvae body is smooth, almost hairless, variably yellowish-green to brown to dark gray, and with several dark stripes interspersed with pale lines along top and sides (Powell and Opler, 2009).