Polyphagous. On more than 40 host genera in 15 families, including Achillea, in Britain and elsewhere. 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, but not primarily above the midrib.

5

5a > Leaf-miner: Mine linear, frequently adjoining mid-rib (Spencer, 1972b: 73).

Upper-surface corridor; the start may be lower-surface. Pupation outside the mine.

Only on Achillea ptarmica in Britain and elsewhere. Widespread in Britain. Also occurs in west and central Europe.

Phytomyza corvimontana Hering, 1930 [Diptera: Agromyzidae].

5b > 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) 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 'atricornis' has been recorded on Achillea in Britain.

Chromatomyia syngenesiae and Chromatomyia horticola are recorded on Achillea elsewhere but not yet on Achillea in Britain.

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

5c > 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 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].

5d > Leaf-miner: A narrow linear mine, even in the finest subdivisions of the leaves (Spencer, 1972b: 77, as matricariae ; Spencer, 1976: 478).

Very fine corridor, upper- or lower-surface, even in the narrowest leaf segments. The corridor may be up to 14 cm long (Sehgal, 1971a). Generally the corridor descends towards the leaf base. Frass in pearl chains of loose grains, hardly in strings. Pupation outside the mine. Very fine corridor, upper- or lower-surface, even in the narrowest leaf segments. The corridor may be up to 14 cm long (Sehgal, 1971a). Generally the corridor descends towards the leaf base. Frass in pearl chains of loose grains, hardly in strings. Pupation outside the mine.

On Achillea millefolium, Anacyclus pyrethrum, Anthemis, Tanacetum vulgare, Tripleurospermum, Tripleurospermum maritimum and Tripleurospermum maritimum x inodora in Britain and other Asteraceae elsewhere. Widespread in Britain and continental Europe. Also recorded in Canada.

Phytomyza pullula Zetterstedt, 1848 [Diptera: Agromyzidae].

5e > Leaf-miner: A linear mine, frequently on lower surface at beginning; frass with closely adjoining grains.

Upper-surface, often brownish, corridor, in the end often occupying the width of a leaf segment. Older segments of the mine are much less conspicuous, lower-surface and quite shallow. Where upper- and lower-surface stretches overlap transparent patches occur, when the leaf is illuminated from behind. Frass in isolated grains, sometimes locally pearl chains. Pupation outside the mine.

On Tanacetum, but not yet on Achillea, in Britain; recorded on Achillea, Leucanthemum, Pyrethrum and Tanacetum elsewhere. Probably widespread in England. Also recorded in the Republic of Ireland: Co. Clare (the Burren) (Spencer, 1972: 79). Widespread in continental Europe

Phytomyza tanaceti Hendel, 1923 [Diptera: Agromyzidae].

4f > 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 Achillea, in Britain, Throughout the British Isles, more common in the south than the north. Also continental Europe.

Trypeta zoe Meigen, 1826 [Diptera: Tephritidae].

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).