Leaf-mine: Large blotch mine, often with several larvae, beginning with a short deeper corridor at a single egg shell on the surface of the leaf. The broad deep corridor later ends in a blotch but can be recognised (beneath the blotch) by its greater depth. Mine predominantly dorsal or ventral, greenish in transmitted light. Frass grains irregularly scattered except in the initial corridor.

Blotch, mostly occupying almos the entire leaf, containing several larvae. Much, half-deliquescent, greenish-black frass. At the start of the mine at the leaf underside a group of some 5 elliptic egg shells, parallel to each other. However, the larvae can leave their mine and restart elsewhere, so mines without egg shells can occur as well. The larvae do not penetrate into the stem of the plant, neither is the mine full depth (compare Delia species) (Bladmineerders van Europa). Mine indistinguishable from P. exilis or P. hyoscyami (Bladmineerders van Europa).

Makes a large upper surface whitish blotch, which can contain several larvae. The frass has a washed out appearance and is greenish. There may be several mines on a leaf and eventually the leaf will be mined and then shrivel up. To identify this miner adults must be reared (British leafminers).

Larva: The eggs and larvae are described d'Aguilar and Missonier (1957 and 1962). The larva is illustrated in Bladmineerders van Europa. Larva with bud-like posterior spiracles.

Puparium: Details unknown.

The adult is ilustrated in the Encyclopedia of Life.

Comments: According to Michelsen (1980) hyoscyami is reliably recorded only from Beta and Chenopodium, Hyoscyamus and Silene. Any earlier records should be regarded as unsubstantiated. Pegomya exilis and Pegomya cunicularia were distinguished from Pegomya betae and Pegomya hyoscyami by Michelsen (1980). Material of both [the former species] had previously been assigned to those [two latter] species (Chandler, pers. comm.).

Chenopodium ambrosioides is treated as Dysphania ambrosioides (Mexican-tea) by Stace (2010).

Hosts in Britain: Chenopodium urbicum (City Goosefoot), Chenopodium album (Fat Hen), Spinacia oleracea (Spinach), Hyoscyamus niger (Stinking Nightshade), Beta vulgaris (Beet), Silene vulgaris (Bladder campion)

Hosts elsewhere:

Time of year - mines: June-September.

Time of year - adults: August.

Distribution in Great Britain and Ireland: Widespread in Britain including Inner Hebrides (Isle of Coll) (Bland, 1992), Warwickshire (Coventry and Chadwick End) (Robbins, 1991), East Kent, Glamorgan, North Somerset, Surrey, West Cornwall and Wigtownshire (NBN Gateway - N.B. includes Watsonian Vice Counties having publicly available records that fall within or overlap the vice county border at 10km resolution or better i.e. a record for a vice county may relate to an adjacent vice county - for included datasets see NBN Grid map below).

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Distribution elsewhere: Widespread in continental Europe including The Netherlands (Bladmineerders van Europa), Andorra, Czech Republic, Denmark, Finland, French mainland, Germany, Norwegian mainland, Russia - Northwest, Spanish mainland and Sweden (Michelsen, in Fauna Europaea).

Also recorded in the East Palaearctic (Michelsen, in Fauna Europaea) and North America (Griffiths, 1982).

NBN interactive distribution map(s) of known host species in Great Britain and Ireland and elsewhere:

Parasitoids in Britain and elsewhere: