Shargacucullia prenanthis, the false water betony, is a moth of the family Noctuidae.

It is found from south-eastern France, through the Alps and bordering mountains east to Romania and Bulgaria.

Forewing violaceous grey, outer half of costal area shaded darker; lower half of submedian fold before the outer line broadly streaked with whitish; stigmata entirely absent; a black streak along inner margin to outer line, and a broader black streak beyond it below vein 2, continued as a fine marginal line to apex and cut by the whiter veins; a row of dark streaks from apex to vein 6; hindwing brown in both sexes, though often paler in the male.

Larva green; dorsal and subdorsal lines yellow, spiracular line white; head green; tubercles yellowish white.

The larvae feed on Scrophularia species, including Scrophularia nodosa first on the flowers and seeds, then on the leaves