Forewing ground colour greyish brown with some scattered white scales, especially in the costal region. Several long longitudinal lines of dark brown scales.

Greyish or yellowish green, pinacula black with greyish hairs; head capsule pale brown; prothoracic plate yellowish.

Very loosely spun cocoon.

The eggs are oviposited during April–May on the larval foodplant, close to an umbel.
The first instar bores into the stem of an umbel and later on it moves to larger side-branches. The last instars move to the main stem even below water-level, in June–July. Just before pupation the last instar bites an emergence hole in the side of the stem and closes this with silk and frass.
Pupation in a loosely spun silken cocoon , sometimes below the water-level.
The adults emerge through the watertight exit hole in July–September. The pupa does not protrude the exit hole before emerging. The species hibernates in the adult stage. Adults have been observed flying around in May during late afternoon sunshine. They are also active at night and come occasionally to light.

The species is mainly found on Apium nodiflorum, but it has also been recorded on other Apiaceae like: Oenanthe aquatica, O. crocata or on Sium latifolium.

Marshes, marginal vegetation around ponds, wet meadows, river borders and dykes.