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

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

2

1b > Leaf-miner

3

2a > Stem miner: A long external whitish stem mine, feeding downwards from a leaf stalk or part of the upper stem. Pupation external (Spencer, 1972b: 41). Puparium yellowish

On Vicia cracca and Vicia sylvatica in Britain. Only known from Hunts and Cambridge in Britain. Also recorded in the Republic of Ireland. Czech Republic, Finland, Germany, Lithuania and Spanish mainland in continental Europe.

Agromyza marionae Griffiths, 1963 [Diptera: Agromyzidae].

2b > Stem miner: An external stem mine. Pupation in the stem, near or even below ground level, with the anterior spiracles projecting through the epidermis (Spencer, 1976: 72-3).

On Lathyrus, Pisum and Vicia in Britain and Lathyrus and Pisum elsewhere. Widespread in the south of Britain. Widespread in much of Europe.

Ophiomyia orbiculata (Hendel, 1931) [Diptera: Agromyzidae].

3a > 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 in Britain including Vicia. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

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

3b > Leaf-miner: Mine not primarily associated with mid-rib.

4

4a > Leaf miner: An initially lower-surface linear leaf-mine, which later develops into large whitish blotch and appears pale and mottled from above, due to the variable depth of larval feeding. Less frequently feeding in upper surface or stem (Spencer, 1972b: 37, fig. 112); Spencer, 1976: 118).

The mine starts as a superficial lower-surface corridor. After its first moult the larva starts making a blotch, often close to the base of the leaflet. The blotch in principle is lower-surface, but may be interparenchymatous for some part. Moreover, in places the larva feeds from the palissade parenchyma. Seen from above the leaf appears mottled. The overall result is that the mine, despite its considerable size, is hard to find. The easiest way is to hold the leaves against the light: the large larvae than are conspicuous. Frass in coarse grains, both in the corridor and in the blotch; in the corridor they are widely spaced. Pupation outside the mine.

Puparium reddish

On Lathyrus grandiflorus, Lathyrus latifolius, Lathyrus rotundifolius, Lathyrus tuberosus and Pisum sativum, but not yet on Vicia, in Britain and additional species and genera of Fabaceae elsewhere. Widespread in southern England - Kent, Surrey, Warwick and Cambridge and Widespread in continental Europe.

Agromyza lathyri Hendel, 1923 [Diptera: Agromyzidae].

4b > Leaf-miner: Mine beginning linear, later becoming a primary blotch (Spencer, 1972b: 42).

Large blotch, preceded by a corridor that meticulously follows the leaf margin. Blotch clearly upper-surface, nowhere mined out deeper than the corridor, and equally transparent. The blotch is not oriented on the midrib. Frass in the corridor in short streaks along the sides, in the blotch as small grains that partly may be deliquescent. Pupation outside the mine.

On Vicia cracca and Vicia sylvatica in Britain. On Vicia cracca, Vicia sylvatica and other Vicia species elsewhere. Uncommon in Britain - Surrey and Warwick. Germany, The Netherlands, Poland, Sardinia and Sweden in continental Europe.

Agromyza bicophaga Hering, 1925 [Diptera: Agromyzidae].

4c > Leaf-miner: A primary blotch-mine, which entirely fills a leaf and usually shows some reddish colouration; frass in distinct grains (Spencer, 1972b: 41).

Oviposition in the tip of a leaflet, Primary blotch without a preceding corridor; distal half mostly a red colouration. The blotch is upper-surface with a few full depth patches, making it look spotty in transparency. Frass in groups of grains. Pupation outside the mine.

On Vicia sativa and Vicia sepium in Britain. On Vicia sepium elsewhere. Only recorded in Surrey and Sussex in Britain. Widespread in continental Europe.

Agromyza felleri Hering, 1941 [Diptera: Agromyzidae].

4d > Leaf-miner: Larva producing a short narrow linear mine not associated with the margin, which then develops into a conspicuous white blotch centred on the mid-rib. At the end of feeding the larva lies for one or two days along the mid-rib. Pupation external (Spencer, 1972b: 37 (fig. 114b); Spencer, 1976: 126, fig. 213A).

Broad and short hook-like upper-surface corridor, ending in a little blotch in the centre of a leaflet. The blotch is upper-surface as well, but has some deep spots, giving the mine a mottled appearance when hold against the light. Frass in the blotch in a few large lumps. Pupation outside the mine.

A short, broad gallery leading to a conspicuous, roundish white blotch in the centre of the leaf. The blotch is upper surface with full depth spots - comprising of large clumps of frass.

Puparium reddish

On Medicago, Melilotus and Trifolium, but not yet on Anthyllis, in Britain and in addition other genera of Fabaceae elsewhere. Common and widely distributed in England. Also recorded in the Republic of Ireland. Widespread and common throughout Europe.

Agromyza nana Meigen, 1830 [Diptera: Agromyzidae].

4e > Leaf-miner: Mine initially linear, adjoining margin of leaf, later developing into a blotch, always on the mid-rib (Spencer, 1976: 145, fig. 265).

Blotch, preceded by a corridor that closely follows the leaf margin. The blotch is mined much deeper (and therefore more transparent) than the corridor. The blotch is precisely positioned over te midrib of the leaflet. Frass very sparingly in the corridor, in the blotch as a few large lumps. Pupation outside the mine.

Forms a blotch over the mid-rib without an initial gallery mine. Frass dispersed.

Mines of Agromyza vicifoliae on Vicia
Image: © Rob Edmunds (British leafminers)

On Vicia cracca, Vicia hirsuta, Vicia sativa and Vicia sepium in Britain. On Vicia cracca, Vicia hirsuta, and Vicia sepium elsewhere. Widespread but local in Britain. Widespread throughout much of Europe.

Agromyza vicifoliae Hering, 1932 [Diptera: Agromyzidae].

4f > Leaf-miner: Oviposition in the tip of a leaflet; this causes an intensive red colouring of the distal part of the leaflet. From there a primary blotch develops, that in the end occupies almost the entire leaflet. At first the mine is upper-surface, but gradually deeper parts of the mine are eaten away, leading to a very transparent mine. Frass fine-grained, quickly deliquescent. Pupation outside the mine.

On Vicia in Britain. On Vicia grandiflora, Vicia hirsuta, Vicia sativa and Vicia sepium elsewhere. Distribution in Britain unknown. Europe including Germany, Poland, Switzerlandand Norway.

Agromyza viciae Kaltenbach, 1872 [Diptera: Agromyzidae]

4g > 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 horticola is recorded on 160 plant genera in 31 families, of which 55 plant genera in 19 families, including Vicia, in Britain.

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

4h > Leaf-miner: An upper surface linear mine with frass in conspicuous greenish strips, largely alternating at each side of the channel. Puparium yellow

Polyphagous. On numerous genera of Fabaceae, including Vicia, in Britain and elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland and widespread and common throughout most of Europe

Liriomyza congesta (Becker, 1903) [Diptera: Agromyzidae].

4i > Leaf-miner: A long linear mine, normally starting on lower surface, frass in black strips alternately at sides of mine (Spencer, 1972b: 58).

Long whitish corridor, almost always lower-surface at first, then becoming largely or totally upper-surface. Because lower- and upper-surface tracts often cross the leaf looks distinctly mottled whe held against the light. The final part of the corridor is generally upper-surface. The corridor often follows a thick vein for a considerable distance. Frass in alternating thread fragments. Pupation outside the mine.

On Lathryus, Pisum and Vicia in Britain and Lathryus and Pisum elsewhere. Only known from Kent, Surrey, Herts and Warwick in Britain. Widespread in continental Europe.

Liriomyza pisivora Hering, 1957 [Diptera: Agromyzidae].

4j > Leaf-miner: A short, irregular, linear upper surface mine on any part of the leaf. Also recorded from young pods (Bland, 1997a).

Long corridor mine. As a rule the first part of the mine is lower-surface, the later part upper-surface. Often the loops are so dense that a secondary blotch is the result. Because upper- and lower-surface corridor segments often cross, the mine obtains a strange array of transparant patches. There is no association with the midrib. Frass in strings and thread fragments. Pupation outside the mine; exit slit in upper epidermis.

Mine not associated with the veins or midrib of the leaf (It is this character which enables distinction from another Agromyzid pest species - Liriomyza huidobriensis). The larvae may leave one leaf (if not large enough) and enter another leaf, via the petiole). It exits the leaf to pupate through a semi-circular slit in the upper surface of the leaf.

Polyphagous. On 119 plant genera in 31 plant families of which only 4 plant genera in 2 plant families, but not yet on Vicia, in Britain. Local, probably introduced to Britain. Widespread in continental Europe particularly in Botanical Gardens and glasshouses. Also recorded in Egypt.

Liriomyza bryoniae (Kaltenbach, 1858) [Diptera: Agromyzidae].

4k > Leaf-miner: A narrow linear mine adjoining the leaf margin in the first instar, which later develops into an irregular blotch with conspicuous lumps of greenish frass (Spencer, 1976: 302).

The first instar larva makes a narrow upper-surface corridor along the leaf margin. After it has moulted it begins a large upper-surface blotch. Frass in conspicuous green lumps, that can run out irregularly. Pupation outside the mine.

Forms a narrow linear mine by the margin of the leaf which later develops into a blotch. The blotch has clumps of greenish frass.

On Astragalus and Colutea, but not yet on Vicia, in Britain and Anthyllis, Astragalus, Cicer, Colutea, Coronilla, Cytisus, Lathyrus, Oxytropis, Securinega and Vicia elsewhere. Widespread in continental Europe.

Phytoliriomyza variegata (Meigen, 1830) [Diptera: Agromyzidae].