The leaf and stem mines of British flies and other insects

(Coleoptera, Diptera, Hymenoptera and Lepidoptera)

by Brian Pitkin, Willem Ellis, Colin Plant and Rob Edmunds


ARTEMISIA. Mugworts and Wormwoods [Asteraceae]

Numerous species of Artemisia are recorded in Britain. Four species are native - Wormwood (A. absinthium), Field Wormwood (A. campestris), Norwegian Mugwort (A. norvegica) and Mugwort (A. vulgaris). An additional seventeen species are introduced, including Tarragon (A. dracunculus), Annual Mugwort (A. annua), Slender Mugwort (A. biennis), Hoary Wormwood (A. stelleriana), Chinese Mugwort (A. verlotiorum) and Shrub Southernwood (A. abrotanum). The BSBI provide a downloadable plant crib for Artemisia.

Field Wormwood (A. campestris) is protected under Schedule 8 of the Wildlife and Countryside Act, 1981.

Eighteen or nineteen Brish miners are recorded on Artemisia.

The polyphagous agromyzid Liriomyza trifolii has been recorded in quarantine in Britain (Pitkin & Plant in British leafminers). See also Liriomyza species in Glasshouses and/or Quarantine Interceptions.).

Although there is a record of the agromyzid Agromyza abiens on Artemisia vulgaris (Robbins, 1991) this is unlikely to be correct, as this species mines Boraginaceae. There is also a record of Aulagromyza discrepans on Artemisia (Robbins, 1991), but as the mine has not previously been described, the record needs confirmation.

The agromyzid Melanagromyza oligophaga bores within the stems of Achillea and Artemisia in Britain.

The coleophorid Coleophora artemisicolella is recorded as a seed-feeder on Artemisia in Britain.

A key to the European miners recorded on Artemisia is provided in Bladmineerders van Europa.

Key for the identification of the known mines of British
Diptera recorded on Artemisia

Note: Diptera larvae may live in a corridor mine, a corridor-blotch mine, or a blotch mine, but never in a case, a rolled or folded leaf, a tentiform mine or sandwiched between two more or less circular leaf sections in later instars. Pupation never in a cocoon. All mining Diptera larvae are leg-less maggots without a head capsule (see examples). They never have thoracic or abdominal legs. They do not have chewing mouthparts, although they do have a characteristic cephalo-pharyngeal skeleton (see examples), usually visible internally through the body wall. The larvae lie on their sides within the mine and use their pick-like mouthparts to feed on plant tissue. In some corridor miners frass may lie in two rows on alternate sides of the mine. In order to vacate the mine the fully grown larva cuts an exit slit, which is usually semi-circular (see Liriomyza huidobrensis video). The pupa is formed within the hardened last larval skin or puparium and as a result sheaths enclosing head appendages, wings and legs are not visible externally (see examples).

See Key to non-Diptera.

1a >Stem-miner: A narrow, inconspicuous stem mine. Pupation at the end of the mine (Spencer, 1976: 64).

Fine, upper- or lower-surface corridor, ending in a thick vein. From there the mine extends finally to the rind of the stem. There also the pupation takes place, usually not far from the root collar. Mines in the stem rind often are conspicuous through a red discoloration.

On Achillea, Achillea millefolium and possibly Anthemis, Matricaria and Medicago sativa, but not yet on Artemisia, in Britain. In Britain widespread in south, not uncommon. On Anthemis, Achillea, Artemisia, Aster, Centaurea, Clinopodium, Crepis, Hieracium, Matricaria, Reichardia, Solidago, Tanacetum, Tripleurospermum, Medicago, Satureja and Stachys elsewhere. Widespread in continental Europe.

Ophiomyia curvipalpis (Zetterstedt, 1848) [Diptera: Agromyzidae].

1b > Leaf-miner


2a > Leaf-miner: Blotch mine.


2b > Leaf-miner: Corridor mine.


3a > Leaf-miner: A whitish-greenish blotch. Pupation external, on the ground (Spencer, 1972b: 43, fig. 140; Spencer, 1976: 306-7, fig. 552).

A chacteristically pale whitish, usually upper-surface, primary blotch. There is an initial corridor, but traces of it are almost always overrun by the later blotch. The mine is quite opaque; only by opening it can it be ascertained if the mine is still occupied. No feeding lines are apparent. Unlike other blotch mines thay may occur here, Calycomyza mines are totally flat. Pupation outside the mine.

A whitish blotch mine occuring on the upper leaf surface. Starts with a short corridor and does not show feeding lines. Superficially similar to the lepidopterous mine made by Leucospilapteryx omissella, but the latter mine turns purple as it ages.

On Artemisia and Eupatorium in Britain and additional Asteraceae elsewhere. Widespread in England and Continental Europe. Also recorded in China, Japan, Colombia and Canada.

Calycomyza artemisiae (Kaltenbach, 1856) [Diptera: Agromyzidae].

3b > Leaf-miner: The mine begins as an elongated blotch overlying a strong vein; from there broad tunnels radiate that coalesce in the end. All frass is concentrated at a central point in the floor of the mine. As a result the mine has a brownish-black centre and a paler brownish green seam. The larva often (perhaps always at daylight) rests in the centre of the mine. Primary and secondary feeding lines as a rule quite clear. Pupation outside the mine.

An elongated blotch centred over a vein. There are two types: greenish with a blackish centre and entirely reddish-black.

Trypeta artemisiae puparia
Trypeta artemisiae pupariria
Image: © Willem Ellis (Bladmineerders van Europa)

On numerous genera of Asteraceae, including Artemisia, in Britain and elsewhere. In Britain more common in the north than in the south. Also throughout the Palaearctic Region except the Mediterranean and Middle Eastern areas.

Trypeta artemisiae (Fabricius, 1794) [Diptera: Tephritidae].

3c > Leaf-miner: Blotch mine (Spencer, 1990: 299).

The mine is a large whitish underside blotch with clear feeding lines and pupation is external (Robbins, 1989: 117).

The mine starts as a star-shaped interparenchymatous blotch near the midrib. This is followed by a broad, corridor-like arc around the central part of the leaf tip. The circumcised section of the leaf dies off and remains as a black patch in the centre of the mine. Primary and secondary feeding lines well visible in fresh leaves. Frass in coarse grains. Often several mines coalesce into one. Pupation outside the mine; semicircular exit slit in the upper epidermis.

On Artemisia in Britain and elsewhere. First recorded from Coventry in Britain. Widespread in continental Europe

Agromyza rufipes Meigen, 1830 [Diptera: Agromyzidae].

4a > Leaf-miner: A distinctive mine primarily above mid-rib, with irregular short lateral offshoots into leaf blade. Pupation external (Spencer, 1972: 51 (fig. 172), 55; Spencer, 1976: 270, 271 (fig. 486)).

Branched, whitish, upper-surface corridor; main axis overlying the midrib; side branches overlying the main lateral veins. (In Campanula and Phyteuma the mine is much less branched, sometimes nothing more than a corridor on top of the midrib). Frass in rather long strings. Usually the mines begins as a long and narrow, shallow, tortuous lower-surface corridor that ends upon the midrib but otherwise is not associated with the leaf venation. Often this initial corridor is filled with callus, and then even less conspicuous. Pupation outside the mine.

A linear mine on the upper surface, usually following the midrib and showing side branches along the veins. The frass is in strings.

Liriomyza strigata larva,  lateral
Liriomyza strigata larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)

Polyphagous. On more than 40 host genera in 15 families, including Artemisia, in Britain. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Liriomyza strigata (Meigen, 1830) [Diptera: Agromyzidae].

4b > Leaf-miner: Mine linear, whitish, both upper and lower surface. Pupation internal, at the end of the mine with the anterior spiracles projecting through the epidermis (Spencer, 1976: 433).

Upper-surface, less often lower-surface corridor. Frass in isolated grains. Pupation within the mine, usually in a lower-surface puparial chamber.

A long whitish upper surface corridor, which eventually goes lower surface.

Two highly polyphagous species of Chromatomyia, with indistinguishable mines, have been recorded in Britain. These are syngenesiae (Hardy) and horticola (Goureau, 1851) which can only be distinguished by the male genitalia. Both species are widespread in Britain and elsewhere, although syngenesiae is almost entirely restricted to Asteraceae. Records on Asteraceae not based on examination of male genitalia are treated in this account as Chromatomyia 'atricornis'.

Chromatomyia syngenesiae is recorded on Artemisia elsewhere but not yet on Artemisia in Britain.

Chromatomyia 'atricornis' has been recorded on Artemisia in Britain.

Chromatomyia horticola (Goureau, 1851) [Diptera: Agromyzidae]
Chromatomyia syngenesiae Hardy, 1849 [Diptera: Agromyzidae].

4c > Leaf-miner: The mine begins as a long, quite narrow corridor, usually not far from the tip of a leaf segment. Usually this corridor follows the leaf margin for some distance, but it may also run freely through the blade and may then be stongly contorted. In the end the corridor is directed towards the midrib, where an elongated blotch is formed, overlying the midrib and some of the larger lateral veins. Frass in a nearly continuous line in the initial corridor, in scattered lumps in the later part of the mine. Primary and secondary feeding lines very conspicuous when seen in transparancy. Pupation outside the mine.

The mine starts as a very narrow corridor, usually close to the tip of a leaf segment and following the leaf margin. The later section of the corridor approaches the main vein, where an elongated blotch is made with long broad finger like extensions that lay over the secondary veins. In the initial corridor the frass forms an almost continuous line, in the blotch it is distributed in large scattered lumps. In fresh mines the secondary feeding lines are clearly visible.

On numerous genera of Asteraceae, including Artemisia, in Britain, Throughout the British Isles, more common in the south than the north. Also continental Europe.

Trypeta zoe Meigen, 1826 [Diptera: Tephritidae].

4d > Leaf-miner: Mine long, whitish, frequently adjoining a vein with frass in separate grains (Spencer, 1976: 387, fig. 675).

Little widening upper-surface corridor, up to 8 cm long; sometimes the first part lower-surface. Often the corridor follows a vein or the leaf margin for some distance. The sides are initially quite smooth, later they may be more irregular. Primary feeding lines often visible. Frass in pearl chains and isolated grains, in two neat rows - closely resembling the frass pattern of Liriomyza's. The whitish larva leaves the mine before pupation; exit slit in upper epidermis.

The mine is a long corridor, which often partly follows the veins of the leaf, or leaf margin. The frass is in separate grains, with the appearance of stings of pearls.

Phytomyza artemisivora puparium. dorsal
Phytomyza artemisivora puparium. dorsal
Image: © Willem Ellis (Bladmineerders van Europa)

On Artemisia in Britain and elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Common and Widespread in continental Europe, range extending eastwards to the Kirghiz Republic of the [former] U.S.S.R.

Phytomyza artemisivora Spencer, 1971 [Diptera: Agromyzidae].

4e > Leaf-miner: Generally associated with mid-rib or leaf margin and relatively long (Spencer, 1976: 243).

Upper-surface corridor, generally descending from the tip of a leaf segment toewards the centre along a vein or the leaf margin. Frass in strings. Pupation outside the mine.

An upper surface gallery of moderate length, mostly alongside a vein. The corridor is long and loose, with stringy frass.

Puparium yellow

Liriomyza demeijerei larva,  lateral
Liriomyza demeijerei larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)

On Artemisia in Britain and elsewhere. Uncommon in Britain. Widespread in continental Europe.

Liriomyza demeijerei Hering, 1930 [Diptera: Agromyzidae].

4f > Leaf-miner: A short rather broad linear mine, usually confined to a single leaf segment. Pupation external (Spencer, 1976: 232).

Upper-surface short and broad corridor, or more often a secondary blotch, normally restricted to the tip of one leaf segment. Frass in strings. The yellow larva leaves the mine before pupation. Feeding punctures lower-surface.

Forms compact, very convoluted mines, with stringy frass.

On Artemisia in Britain and elsewhere. Widespread in Britain and central and western Europe.

Liriomyza artemisicola Meijere, 1924 [Diptera: Agromyzidae].

4g > Leaf-miner: A narrow linear mine, with frass in black strips (Spencer, 1972b: 57; Spencer, 1976: 274). Narrow upper-surface corridor.

The corridor often follows nerves, causing it to branch now and then. Frass in strings. Pupation outside the mine.

Puparium yellowish-black
Mine of Liriomyza tanaceti on Tanacetum vulgare. Image: © Willem Ellis (Source: Bladmineerders en plantengallen van Europa)
Mine of Liriomyza tanaceti on Tanacetum vulgare
Image: © Willem Ellis (Bladmineerders van Europa)

On Artemisia, Chrysanthemum and Tanacetum in Britain and Tanacetum elsewhere. Known only from Surrey and Warwick in Britain. Widespread and not uncommon in much of western Europe

Liriomyza tanaceti Meijere, 1924 [Diptera: Agromyzidae].

4e> Leaf-miner: A narrow linear mine commencing on lower surface (Spencer, 1972b: 57; Spencer, 1976: 264).

Narrow brownish corridor, either upper- or lower-surface. Frass in strings or pearl chains. Pupation outside the mine. In small leaves the mine can be full-depth and occupy the entire leaf. At least in Achillea millefolium mines are generally found in the top half of the leaf.

On Achillea ptarmica and Achillea millefolium, but not yet on Artemisia, in Britain and elsewhere and other species of Achillea elsewhere. Probably widespread in Britain, at least in south. Widespread in continental Europe and also recorded from Canada.

Liriomyza ptarmicae Meijere, 1925 [Diptera: Agromyzidae].


Key for the identification of the known mines of British
non-Diptera recorded on Artemisia

Note: The larvae of mining Coleoptera, Hymenoptera and Lepidoptera may live in a corridor mine, a corridor-blotch mine, a blotch mine, a case, a rolled or folded leaf, a tentiform mine or sandwiched between two more or less circular leaf sections in later instars. Larva may pupate in a silk cocoon. The larva may have six legs (although they may be reduced or absent), a head capsule and chewing mouthparts with opposable mandibles (see video of a gracillarid larva feeding). Larvae of Hymenoptera and Lepidoptera usually also have abdominal legs (see examples). Frass, if present, never in two rows. Unless feeding externally from within a case the larva usually vacates the mine by chewing an exit hole. Pupa with visible head appendages, wings and legs which lie in sheaths (see examples).

1a > Leaf-miner and case-bearer: The larva lives outside the mine, protected by a case, and feeds on the underlying plant tissues via a hole cut in the epidermis. From that point it eats away as much leaf tissue as it can reach without fully entering the mine. Mine does not contain frass (Coleophora species)


1b > Leaf-miner, but not a case-bearer: The larva lives inside the mine. Mine usually contains frass


2a > Leaf-miner and case-bearer: A straw-coloured to grey, slender, three-valved case of he type tubular silken case; mouth angle 45° - 60°. The case resembles that of C. trochilella, but the case is more slender, the mouth is narrower and the constriction behind the mouth less deep.

On Achillea millefolium, Achillea ptarmica, Artemisia maritima, Leucanthemum vulgare and Tanacetum vulgare elsewhere. Recorded in North Hants and South Hants in Britain. Widespread in other parts of Europe and elsewhere.

Coleophora gardesanella Toll, 1954 [Lepidoptera: Coleophoridae].

2b > Leaf-miner and case-bearer: A straw-coloured, slender, three-valved tubular silken case; length about 10 mm, mouth angle 45° - 60°. Larva on the leaf underside. Perhaps because of the plant's dense felt cover, the case is attached with much silk, giving the holes a conspicuous white margin.

On Achillea millefolium, Artemisia absinthium, Artemisia vulgaris, Aster, Leucanthemum vulgare, Tanacetum vulgare and possibly Hieracium in Britain and Achillea millefolium, Artemisia absinthium, Artemisia vulgaris, Leucanthemum vulgare, Tanacetum vulgare elsewhere. Widespread in Britain although there aren't many records. Widespread in continental Europe.

Coleophora trochilella (Duponchel, 1843) [Lepidoptera: Coleophoridae].

2c > Leaf-miner and case-bearer: Laterally strongly compressed, two-valved, black silken case, narrowed behind the mouth. Rear end narrowed, strong ventral keel. Mouth angle c. 0°.

On Artemisia maritima in Britain and Achillea millefolium and Artemisia campestris elsewhere. Britain including South Essex. Widespread in continental Europe.

Coleophora vibicigerella Zeller, 1839 [Lepidoptera: Coleophoridae].

2d > Leaf-miner and case-bearer:: The larva starts to mine the leaves and then later feeds on flowers and seeds (British leafminers, as C. artemisiella). Squat tubular silken case of 6-7 mm. The front half is covered with felt, the rear half is greyish with some darker length lines. The case is trivalved, the mouth angle is c. 15-30°. The larva not only lives on the leaves, but also feeds in the inflorescence.

On Artemisia in Britain and elsewhere. Found on the edges of salt marshes on the East coast in Britain. Widespread in continental Europe.

Coleophora albicans (Zeller) [Lepidoptera: Coleophoridae].

3a > Leaf-miner: In the first instar the larva mines the leaves, forming short, irregular, blotch-like mines, but in later instars it lives externally, feeding in spun leaves and often twisting those of tender shoots. Larval head light-brown or yellowish brown, edged with black postero-laterally, ocellar area blackish; prothoracic plate black edged with whitish anteriorly; abdomen dull dark green; pinacula distinct, black, sometimes brownish but with black bases to setae; anal plate large, black (Bradley et al., 1973). Small, full depth mine without a definite shape; little frass. Some silk is deposited in the mine. The larva soon leaves the mine and continues feeding among spun leaves.

Polyphagous. On numerous genera and species of plant families, but not yet on Artemisia, in Britain. On numerous genera and species of plant families including Artemisia elsewhere. Widespread in Britain and continental Europe. Also recorded from the Channel Is.

Cnephasia incertana (Treitschke, 1835) [Lepidoptera: Tortricidae].

3b > Leaf-miner: The larva feeds initially in a gallery on the underside of a mugwort leaf, eventually forming a blotch or blister that becomes inflated and turns at first yellowish, and later purple. Upper surface blotch, with a conspicuous yellow-orange tinge (older mines turn brown). The larva lines the inside with much silk, causing the mine to pucker up strongly (the inflated surface and the mostly orange tinge distinguish the mine easily from that of Calycomyza artemisiae [Diptera: Agromyzidae] on the same host plant). The mine is preceded by a long lower-surface corridor, running along the midrib or the leaf margin (but practically invisible because of the densely hairy leaf underside). When the larva is almost full-grown it starts eating parts of the upper epidermis, giving the older mines a mottled appearance. Black frass in the centre of the mine. Pupation external.

On Artemisia in Britain and elsewhere. Distributed mainly in the south and east of England. Widespread in continental Europe.

Leucospilapteryx omissella (Stainton, 1848) [Lepidoptera: Gracillariidae].

3c > Leaf-miner: The mine is brownish and extends along the midrib, sometimes branching. Oviposition on top of the midrib. Immediately after emergence the larva gnaws a cavity in the midrib, and from there an irregular blotch is made adjacent to the midrib. The larva continues living in the midrib that is gradully hollowed out, making from there broad, brownish, full depth excursions in the blade. The mine contains much frass; most of it is concentrated in the area immediately bordering the midrib. Older, no longer occupied parts of the mine often split open. Mines mainly on the lower leaves. The slender larvae move surprisingly fast upon disturbance; when they rest (in daytime) they lie lengthwise in the hollowed midrib. Pupation outside the mine.

On Artemisia, Carduus, Cirsium and possibly Tussilago in Britain and Carduus and Cirsium elsewhere. Widespread in Britain and continental Europe.

Scrobipalpa acuminatella (Sircom, 1850) [Lepidoptera: Incurvariidae].

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