Triticum [Poaceae] in Leaf and stem mines of British flies and other insects

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

TRITICUM. Wheats. [Poaceae]

Seven species of Triticum are recorded in Britain. All are introduced and include Bread Wheat (T. aestivum) and Rivet Wheat (T. turgidum).

Twenty-four British miners are recorded on Triticum.

Nearly 100 British miners or possible miners are recorded on grasses in Britain.

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

It is recommended that adults of all miners on grasses be reared to be certain of their identity.

Bread Wheat
Triticum aestivum

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

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 > Leaf-miner: Larvae feed singly, forming an upper surface linear-blotch mine. Pupation either internal or external, with the puparium loosely glued to the leaf (Spencer, 1976: 91).

Oviposition near the leaf margin, at some distance from the leaf tip. From there develops an upper-surface corridor-blotch. At first the mine ascends as a narrow corridor towards the leaf tip, then the direction turns and the mine, steadily widening, descends in the direction of the leaf base. Frass irregular, in rather coarse grains. Larva solitary. Pupation mostly outside the mine; in that case the puparium often sticks to the leaf.

Mine of Agromyza albipennis on Phalaris arundinacea. Image: © Willem Ellis (Source: Bladmineerders en plantengallen van Europa)

Mine of Agromyza albipennis on Phalaris arundinacea
Image: © Willem Ellis (Bladmineerders van Europa)

On Arrhenatherum, Brachypodium, Bromus, Dactylis, Glyceria, Holcus, Hordeum, Milium, Phalaris and Poa, but not yet on Triticum, in Britain and additional grasses, including Agrostis, elsewhere. Widespread and common in Britain. Also recorded in the Republic of Ireland. Very common in western Europe and recorded in Canada.

Agromyza albipennis Meigen, 1830 [Diptera: Agromyzidae].

1b > Leaf-miner: Leaf-mine normally short and broad (Spencer, 1976: 97). According to Hering (1957) initially the larva does not feed towards the apex of the leaf. Pupation external (Spencer, 1976: 97).

The shallow, whtish mine starts (not very close to the base of the lamina) as a fine ascending corridor. This is overrun when the direction alternates, and the mine quickly widens. The final mine is characteristically short; often not the full width of the leaf is used. Frass in big black grains, never greenish. Pupation outside the mine.

On Avena, Hordeum and Secale, but not yet on Triticum, in Britain and in addition on Elytrigia and Triticum elsewhere. Widespread, but local, in Britain. Common and Widespread in continental Europe. Also recorded in Canada and America.

Agromyza ambigua Fallén, 1823 [Diptera: Agromyzidae].

1c > Leaf-miner: Long upper-surface corridor usually containing several larvae that graze shoulder to shoulder from the leaf tip downwards. Pupation outside the mine. Mines and larvae are indistinguishable from those of A. nigrella.

On Bromus, Bromopsis, Elymus, Holcus, Phleum and Triticum in Britain and additional grasses elsewhere. Widespread in Britain and continental Europe.

Agromyza mobilis Meigen, 1830 [Diptera: Agromyzidae].

1d > Leaf-miner: Larval leaf-mine starts as a narrow channel running towards apex of leaf but later develops into a broad blotch running downwards. Frass largely diffused, giving the mine a characteristic greenish appearance. Pupation external (Spencer, 1976: 126).

Corridor, usually several in one leaf, running from close to the leaf base up to near the tip, then reversing direction and widening, resulting in one communal mine in which the larvae descend in a common front. Frass somewhat deliquescent, mine therefore strikingly green. Pupation outside the mine. Neither mine nor larva distinguishable from those of mobilis.

Puparium reddish brown

On Dactylis, Festuca, Glyceria, Holcus, Lolium, Phleum, Poa, Secale, Setaria, Trisetum and Triticum in Britain and additionally other genera of grasses elsewhere. Widespread in Britain. Common and widespread thoughout much of Europe. Also recorded in the U.S.A.

Agromyza nigrella (Rondani, 1875) [Diptera: Agromyzidae].

1e > Leaf-mine: Larva forms a broad mine beginning at the apex of the leaf (Spencer, 1976: 136).

Host in Britain unknown. On Triticum elsewhere. Added to British checklist by Deeming (1995). Widespread in continental Europe.

Agromyza prespana Spencer, 1957 [Diptera: Agromyzidae].

1f > Leaf-mine: Blotch, near the leaf tip, containing one or two larvae; pupation outside the mine.

Hosts in Britain unknown. On Hordeum, Secale and Triticum elsewhere. Added to British checklist by Cole in Chandler (1998: 136). Recorded from Cambridgeshire (NBN Gateway). Also recorded in the Republic of Ireland (Martinez in Fauna Europaea). Widespread in continental Europe

Agromyza luteitarsis (Rondani, 1875) [Diptera: Agromyzidae].

1g > Leaf-miner: Broad corridor, starting not far from the base of the blade, running upwards. Frass deliquescent, only few grains recognisable, mine greenish. Larva solitary. Pupation outside the mine. Puparium reddish brown

On Secale cereale in Britain and Bromus, Hordeum, Secale and Triticum elsewhere. Only known from Oxford, Cambridge and Hunts in Britain. Widespread in continental Europe. Also recorded in Tunisia.

Agromyza intermittens (Becker, 1907) [Diptera: Agromyzidae].

1h > Leaf-miner: The young larva first feeds towards the apex of the leaf, later turning and feeding downwards. Several larvae can occur together in a single leaf. Pupation external (Spencer, 1976: 130).

Upper-surface, greenish, gradually widening corridor, at first running towards the leaf tip, then reverses. Through fusion of several mines the final mine is often communal. Frass in backish green grains, often washed out. Pupation outside the mine.

Puparium reddish brown

Mine of Agromyza nigrociliata on Arrhenatherum elatius. Image: © Willem Ellis (Source: Bladmineerders en plantengallen van Europa)

Mine of Agromyza nigrociliata on Arrhenatherum elatius
Image: © Willem Ellis (Bladmineerders van Europa)

Agromyza nigrociliata puparium
Image: © Willem Ellis (Bladmineerders van Europa)

On Arrhenatherum, Dactylis, Elymus, Hordeum, Phalaris, Secale and Triticum in Britain and additional genera of grasses elsewhere. Widespread in Britain and continental Europe. Also recorded in the East Palaearctic.

Agromyza nigrociliata Hendel, 1931 [Diptera: Agromyzidae].

1i > Leaf-miner: Mine greenish with only single larva, initially running towards apex of leaf before turning back down and developing into a broad blotch (Spencer, 1972b: 32, fig. 84; Spencer, 1976: 140, fig. 251).

Deep, transparant corridor-blotch. The mine begins not far from the leaf apex, at first running upwards as a narrow corridor, then reverses and quickly widens to a blotch. A single larva per mine. Frass in isolated grains. Pupation inside or outside the mine.

The mine is illustrated in the Encyclopedia of Life.

Puparium reddish brown

On Arrhenatherum, Bromus, Calamagrostis, Poa, Secale and Triticum in Britain and additional grasses elsewhere. Widespread in Britain and continental Europe.

Agromyza rondensis Strobl, 1900 [Diptera: Agromyzidae].

1j > Leaf-miner: A linear mine running towards the apex of the leaf and this can widen and become almost blotch-like. Pupation internal (Spencer, 1976: 194, 195 (fig. 340).

Upper surface corridor, mostly in the lower half of the blade, running upwards, and never occuping more than half the width of the leaf. Larva solitary. Frass in green smears. Pupation inside the mine.

On Dactylis, Elymus, Phalaris and Triticum in Britain and additional genera of grasses in continental Europe. Uncommon in England. Widespread in continental Europe. Also recorded in Japan and Canada.

Cerodontha lateralis (Macquart, 1835) [Diptera: Agromyzidae].

1k > Leaf-miner: Larva feeds mainly in the leaf sheaths. The short mines which may be formed in the leaf blade may be easily overlooked. Pupation internal (Spencer, 1976: 178).

Mine begins as a narrow, usually upper-surface, occasionally lower-surface or interparenchymatous corridor in the blade, that descends towards the ligule, thence continues into the leaf sheath, generally on its inside. Usually only one mine per leaf. Puparium in a puparial chamber at the margin of the leaf sheath. Neither mine nor larva can be distinguished from that of C. fulvipes that, as far as is known, only feeds on Poa trivialis.

On Alopecurus, Elymus, Festuca, Holcus and Phalaris, but not yet on Triticum, in Britain (including the Channel Is.) and additional grasses, including Elytrigia, elsewhere. Widespread from the southern England to Scotland, most northerly record Outer Hebrides. Also recorded in the Republic of Ireland, Europe, Africa and Japan.

Cerodontha denticornis (Panzer, 1806) [Diptera: Agromyzidae].

1l > Leaf-miner: Broad elongated mine; the form is dependent of the leaf form of the host plant. Frass green. Usually a number of larvae together in a mine. Pupation in the mine.

On Bromopsis, Dactylis, Elymus and Phalaris, but not yet on Triticum, in Britain and additional grasses, including Elytrigia, elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread and common in continental Europe. Also recorded in Japan, U.S.A. and Canada.

Cerodontha incisa (Meigen, 1830) [Diptera: Agromyzidae].

1m > Leaf-miner: A linear mine running towards the apex of the leaf and this can widen and become almost blotch-like. Pupation internal. Puparium brownish-black

On Dactylis, Elymus, Phalaris and Triticum, but not yet on Triticum, in Britain and additional genera of grasses, including Elytrigia, in continental Europe. Uncommon in England. Widespread in continental Europe. Also recorded in Japan and Canada.

Cerodontha lateralis (Macquart, 1835) [Diptera: Agromyzidae].

1n > Leaf-miner: Normally several larvae feed together. Pupation in the mine (Spencer, 1976: 198).

Broad elongated blotch. Frass greenish. Larvae generally communal. Pupation within the mine. The black puaria are individially anchored within the mine with a silken thread attached at their rear end. Distinguishable from C. incisa only by means of the larva.

On Arrhenatherum, Brachypodium, Bromus, Bromopsis, Calamagrostis, Dactylis, Deschampsia, Elymus, Festuca, Holcus, Lolium, Molinia and Phalaris, but not yet on Triticum, in Britain and additional grasses elsewhere. Widespread and common in Britain. Also recorded in the Republic of Ireland. Widespread and frequently common in much of Europe. Also recorded in Alaska and Canada.

Cerodontha pygmaea (Meigen, 1830) [Diptera: Agromyzidae].

1o > Leaf-miner: Upper-surface corridor, generally in the upper half of the blade, running up to the leaf tip, usually occupying more then half the width of the leaf. Frass in green stripes at either side of the corridor. Never more than one larva in a mine. Puparium within the mine, metallic black, not anchered with a string of silk.

On Ammophila and Elymus, but not yet on Triticum, in Britain and additional grasses including Elytrigia, elsewhere. Known only from Norfolk and Elgin in Britain. Widespread in continental Europe. Also recorded in Canada and the U.S.A.

Cerodontha superciliosa (Zetterstedt, 1860) [Diptera: Agromyzidae].

1p > Leaf-miner: Long, narrow, whitish mine. Pupation internal (Spencer, 1976: 453); anterior spiracles projecting through the epidermis.

Whitish, upper-surface, rather narrow corridor with comparatively large frass grains that are laying further apart than their diameter. Pupation within the mine. The anterior spiracles of the orange-brown puparium penetrate the epidermis.

Chromatomyia nigra larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)

Chromatomyia nigra pupa, lateral
Image: © Willem Ellis (Bladmineerders van Europa)

On numerous genera of grasses, incluidng Triticum, in Britain. Widespread and common throughout British Isles and much of Europe. Also recorded in Canada, western U.S.A. and Japan.

Chromatomyia nigra (Meigen, 1830) [Diptera: Agromyzidae].

1q > Leaf-miner: Narrow whitish mine, with frass in distinct black lumps. Pupation internal (Spencer, 1976: 422).

Whitish, upper-surface, descending corridor, about halfway up the blade. Frass in distinct black grains that are lying further apart than their diameter. Pupation in the mine.

On Arrhenatherum, Holcus, Milium and Phleum, but not yet on Triticum, in Britain and additional grasses elsewhere. Recorded in Scotland and Widespread in continental Europe. Also recorded in Canada.

Chromatomyia fuscula (Zetterstedt, 1838) [Diptera: Agromyzidae].

1r > Leaf-miner: A short narrow mine, generally near apex of leaf. Larva with each segment bearing a row of characteristic papilli which are retained in the puparium (Spencer, 1976: 328). Pupation internal.

Transparent, short and narrow mine not far from the leaf tip. Frass in two rows of grains. Pupation outside the mine.

On Avena, Dactylis, Holcus, Hordeum, Lolium, Phalaris, Phragmites, Poa and Secale, but not yet on Triticum, in Britain and additional other genera of grasses elsewhere. Widespread, but local, in south of Britain. Widespread in continental Europe. Also recorded in Canada.

Pseudonapomyza atra (Meigen, 1830) [Diptera: Agromyzidae].

1s > Leaf-miner: Irregular mine, locally shallow, elsewhere much deeper, giving it a mottled appearance. In broadleaved plants the mine often begins as a blotch with stellate extensions, but sometimes as a very fine, shallow corridor. In grasses the mine often begins in the leaf sheath. The frass is very fine-grained, initially scattered, later in aggregates. The egg is deposited on the plant surface, and the empty egg shell remains visible. But the larvae are able to leave their mine and restart elsewhere, thus mines without an egg shell can be found as well. The larva also leaves the mine before pupation. Pupation takes place in a newly made, small, blotch mine without frass; this mine may be made in another plant (species).

Mine of Hydrellia griseola on Glyceria fluitans. Image: © Willem Ellis (Source: Bladmineerders en plantengallen van Europa)

Polyphagpus. On ? Alisma, ? Damasonium, ? Sagittaria, ? Bellis, ? Rorippa, Tropaeolum, ? Lychnis, ? Stellaria, ? Carex, ? Cyperus, ? Scirpus, ? Hydrocharis, ? Stratiotes, ? Lamium, ? Lemna, ? Allium, Arrhenatherum, ? Polygonum, ? Potamogeton, ? Veronica, ? Typha, but not yet on Triticum, in Britain.

On ? Alisma, ? Damasonium, ? Sagittaria, ? Bellis, ? Rorippa, Tropaeolum, Lychnis, ? Stellaria, Carex, ? Scirpus, Trifolium, ? Hydrocharis, Lamium, ? Lemna, Allium, Papaver, Agrostis, Alopecurus, Apera, Arrhenatherum, Avena, Avenula, Brachypodium, Briza, Bromus, Calamagrostis, Dactylis, Desmazeria, Digitaria, Echinochloa, Eleusine, Elymus, Festuca, Gaudinia, Glyceria, Holcus, Hordeum, Lagurus, Lolium, Panicum, Phalaris, Phleum, Phragmites, Poa, Secale, Setaria, Triticum, ? Polygonum, ? Potamogeton, Veronica, ? Typha and Verbena elsewhere. Widespread in England. Also recorded in the Republic of Ireland. Widespread in the Palaearctic region. Also recorded from Nearctic and Australasian Regions.

Hydrellia griseola (Fallén, 1813) [Diptera: Ephydridae].

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

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).

1# > Leaf-miner: Details unknown

On Poaceae in Britain, On Bromus, Elytrigia, Hordeum, Melica, Secale and Triticum elswhere. Widespread in Britain and continetal Europe. Also recorded in the Republic of Ireland and Northern Ireland

Ochsenheimeria urella Fischer von Röslerstamm, 1842 [Lepidoptera: Ypsolophidae].

1a > Leaf/Stem miner: The larvae mine the stems of various coarse grasses (UKMoths; Plant in Pitkin & Plant, 2005).

The larva mines just a few days in the leaf, then continues as a stem borer on the lower part of the stem. They regularly move to a new stem. The central leaves of the infested plants wither and die.

On Dactylis and Poa, but not yet on Triticum, in Britain and Alopecurus, Avena, Bromus, Dactylis, Hordeum, Poa, Secale andelsewhere. Widespread in England and Wales. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Ochsenheimeria taurella (Denis & Schiffermüller, 1775) [Lepidoptera: Ypsolophidae].

1b > Leaf-miner and Stem-borer: The first instar lave mines in a leaf; after that it lives as a stem borer.

Hosts in Britain unknown. On Elytrigia, Bromus, Bromopsis, PHleum, Poa, Secale and Triticum elsewhere. Widespread in Britain and continental Europe.

Ochsenheimeria vacculella Fischer von Röslerstamm, 1842 [Lepidoptera: Ypsolophidae].

1c > Leaf-miner: The larva mines from the grass tip downwards and the mine occupies half or the whole of the leaf blade width. A whitish blotch is formed with characteristic narrow streaks of frass. Full depth blotch, slightly inflated, descending from the leaf tip, occupying half or the entire width of the blade. The larva may move and make a new mine elsewhere. In the latter case the mines are fairly short; otherwise an entire blade may be mined out. Frass in a some narrow greyish brown streaks. Pupation outside the mine.

On Dactylis, Deschampsia and Holcus, but not yet on Triticum, in Britain plus Luzula, Agrostis, Alopecurus, Arrhenatherum, Avena, Avenula, Brachypodium, Bromus, Calamagrostis, Elymus, Festuca Koeleria, Phalaris, Phleum, Poa, Trisetum and Triticum elsewhere. Widespread in Britain, Ireland and continental Europe.

Elachista albifrontella (Hübner, 1817) [Lepidoptera: Elachistidae].

1d > Leaf-miner: The larvae mine the blades of various grasses, including meadow-grass and cock's-foot. Long, flat, whitish, relatively broad corridor descending from the leaf tip. Frass irregularly scattered. The larva may make several mines during its lifetime. Pupation outside the mine.

On Dactylis, Holcus and Poa, but not yet on Triticum, in Britain plus Agrostis, Bromus, Festuca, Holcus, Koeleria, Trisetum and Triticum elsewhere. Widespread and reasonably common throughout much of the British Isles except the very far north. Widespread in continental Europe.

Elachista freyerella (Hübner, 1825) [Lepidoptera: Elachistidae].

1e > Leaf-miner: Larva makes a large whitish blotch and mines the leaf downwards. The frass tends to be deposited in the upper part of the mine. Oviposition usually not far from the leaf tip. From there descends an irregular blotch mine. Hering (1957a) describes the mine as flat and quite shallow, giving it a greenish, rather than whitish appearance. Frass initially in the oldest, upper part of the mine, later in strings. The larva can leave its mine and restart elsewhere. Normally only one larva per mine, but sometimes two or even three mines in a leaf. Pupation outside the mine.

On Dactylis, Phalaris, Phragmites and Poa, but not yet on Triticum, in Britain plus Agrostis, Alopecurus, Arrhenatherum, Brachypodium, Calamagrostis, Elymus, Festuca, Holcus, Trisetum and Triticum elsewhere. Widely distributed in Britain, Ireland and continental Europe.

Elachista maculicerusella (Bruand, 1859) [Lepidoptera: Elachistidae].


	Last updated 28-Mar-2018 Brian Pitkin