Diagnosis. S. plagicolella is in external characters similar to S. poterii, S. filipendulae and S. ulmariae (all of the aurella group) and S. prunetorum which also has the same host plant; prunetorum has a black frontal tuft and the species of the aurella group have very different genitalia. The male genitalia are unlike those of all externally similar species. The female genitalia are unique in having the ring of pectinations encircling the vestibulum.
Male. Wingspan: 4.0-5.0 mm. Head: frontal tuft ochreous-yellow; collar dark brown; scape pale yellow, antenna three-fifths length of forewing. Thorax bronzy brown. Forewing: area proximal to fascia bronzy, darker towards fascia and with bluish sheen; fascia broad, pale golden; distal to fascia blackish with strong bluish reflections; terminal cilia dark grey. Hindwing: dark grey, slightly darker towards tip; cilia grey. Abdomen blackish grey, with small grey-brown anal tufts. Female. Wingspan: 4.0-5.0 mm. Antenna to midlength of forewing. Abdomen pointed, without tufts. Male genitalia. Vinculum long, hind margin deeply emarginate. Uncus small with deep medial notch and distinct paramedial notches. Tegumen narrow. Gnathos with short, close-set horns forming a V. Valva short and broad, two distal processes short. Transtilla with short sublateral processes. Aedeagus long, with numerous spines of varying sizes, a few large cornuti near tip and a triangular sclerotization at tip. Manica large, distinctly spined. Female genitalia. Corpus bursae long, almost parallel- sided; almost entire corpus with pectinations, anterior end with coarse, scale-like pectinations. Accessory sac absent. Ductus spermathecae shorter than corpus. Vestibulum with a circular band with fine pectinations. Apophyses short, anteriores and posteriores of subequal length; ovipositor not protruding.
Host plants: Prunus spinosa, Prunus domestica (sometimes as pest), occasionally also on Prunus avium and other Prunus species; also reported from Prunus grown in glasshouses. Egg: on underside of leaf, generally near midrib. Larva: pale whitish yellow, head reddish brown. Mine : a slender, slightly sinuous gallery abruptly widening into a large oval blotch. Frass in narrow central line in gallery, scattered in the centre of the blotch. Cocoon: pale brown.
In eastern Denmark, including F. In Sweden up to Vstm. Not in Norway and Finland; Grönlien's (1932) records from Norway cannot be verified. - British Isles, Ireland, and widely distributed in central and southern Europe.
Voltinism: with two generations per year. Mines in June-July and September-October, adults are known from June and August in Scandinavia.
Description based on Johansson and Nielsen (1990)