Key for the identification of the known mines of British
insects (Diptera and non-Diptera) recorded on Chrysanthemum

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). A relatively large (12-15 mm), dark brown, lightly curved two-valved sheath case with a narrow ventral keel. Mouth angle 30-45.

On Centaurea nigra, but not yet on Chrysanthemum, in Britain and Aster, Centaurea, Chrysanthemum and Scabiosa elsewhere. Recorded from South Essex in Britain. Widespread in continental Europe.

Coleophora conspicuella Zeller, 1849 [Lepidoptera: Coleophoridae].

1b > Leaf-miner, but not a case-bearer:

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2a > 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.

On numerous genera of Asteraceae, including Chrysanthemum, 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].

2b > Leaf-miner: The larva feeds in a leaf-mine to begin with, then later feeds externally on the leaves, shrivelling and blanching or browning them. Initially an extremely fine corridor along the leaf margin; these mines mainly in the lower leaves. Frass in a narrow central line. The larva can leave its mine and restart elsewhere. Older larvae live free, and feed by slicing open the margin of a leaf segment near its tip and eating away as much tissue as it can reach (to about one third if its body length). The result is a number of full depth blotch mines. When the larva has become too large even for this strategy, its starts to feed freely on the leaf. The larva pupates in a distinctive whitish ribbed cocoon.

On Achillea millefolium, but not yet on Chrysanthemum, in Britain and also Anthemis tinctoria, Chrysanthemum and Leucanthemopsis alpina elsewhere. Fairly widespread in England. Widespread in continental Europe.

Bucculatrix cristatella (Zeller, 1839) [Lepidoptera: Bucculatricidae].

2d > 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 several plant families, including Chrysanthemum, in Britain and elsewhere. Widespread in Britain and continental Europe. Also recorded from the Channel Is.

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

2e >Leaf-miner: Linear mine.

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3a > 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.

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 [Diptera: Agromyzidae].

3b > Leaf-miner: Mine not primarily associated with the mid-rib. 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 horticola is recorded on 160 plant genera in 31 families of which 55 plant genera in 19 families, but not Chrysanthemum, in Britain. On Chrysanthemum elsewhere.

Chromatomya syngenesiae is recorded in Britain on 27 plant genera in the family Asteraceae and many more genera elsewhere, including Chrysanthemum, in Britain. On Chrysanthemum elsewhere.

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

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

3c > Leaf-miner: Mine irregularly linear, whitish, distinctly widening, most frequently on lower leaves. Pupation external (Spencer, 1972b: 79).

Long, slender corridor, gnerally upper-surface with a lower-surface beginning. Frass in irregular, but not conncted, grains. Pupation outside the mine.

A long, irregular galley which widens distinctly, upper surface, but often starting lower surface and sometimes forming a secondary blotch. Most frequently on lower leaves.

On Leucanthemum x superbum and Leucanthemum vulgare, but not yet on Chrysanthemum, in Britain and elsewhere and Chysanthemum species elsewhere. Widespread but local in Britain & Ireland. Widespread and not uncommon in many parts of Europe.

Phytomyza leucanthemi Hering, 1935 [Diptera: Agromyzidae].

3c > Leaf-miner: Mine primarily associated with the mid-rib.

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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.

Polyphagous. On more than 40 host genera in 15 families, including Chrysanthemum, 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: A broad linear mine following the mid-rib, with irregular lateral offshoots. Puparium yellow

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

Trypeta zoe Meigen, 1826 [Diptera: Tephritidae].

4c > Leaf-miner: Broad corridor overlying the midrib. The mine has a number of side branches that distally widen strongly, and may coalesce. Primary and secondary feeding lines very conspicuous. Pupation external, in soil.

On Aster and Solidago, but not yet on Chrsyanthemum, in Britain, possibly also Cirsium elsewhere. In Britain Recently recorded only from Kent and Perth. There are old records (pre-1960) for Hereford and Lancaster.

Cornutrypeta spinifrons (Schroeder, 1913) [Diptera: Tephritidae].