Udea ferrugalis, the rusty dot pearl, is a moth of the family Crambidae. The species was first described by Jacob Hübner in 1796.
This species can be found in central and southern Europe, Asia Minor, Africa, India and Japan.
The wingspan is 18–22 mm. The forewings of these small moths have yellow, brown or ferruginous ground colour and prominent indistinct dark brown or blackish markings towards the edge. Hindwings are brownish grey.[4] Legs are whitish. Caterpillars can reach a length of 10–15 millimetres (0.39–0.59 in). They are greenish with yellowish head.
These moths are bivoltine or trivoltine. The moth flies through the year, but mainly in the autumn, depending on location. The larvae feed on various herbaceous plants, such as Stachys, Arctium, Lycopus, Mentha, Eupatorium cannabinum and Fragaria vesca. They overwinter in the soil as a chrysalis. This species is sometimes considered a pest, as the larvae attack various crop plants.
Wingspan 18-22 mm.
The ferruginous ground colour and blackish markings on the forewing help to identify this species. Like several of its congeners, it shows distinctively whitish legs.
In Britain this moth is mainly a migrant species, but can occur at almost any time of the year, sometimes in large influxes with other migrants.
The adult flies at night and comes to light.
