POPULUS. Poplars and Aspens. [Salicaceae]

Ten species of Populus are recorded in Britain. These include the native Black-poplar (P. nigra), White Poplar (P. alba) and Aspen (P. tremula) and the introduced American Aspen (P. tremuloides), Eastern Balsam-poplar (P. balsamifera) and Western Balsam-poplar (P. trichocarpa).

Four Diptera miners, the agromyzids Agromyza albitarsis, Aulagromyza populi, Aulagromyza populicola and Aulagromyza tremulae, are recorded on Populus in Britain.

The agromyzid Hexomyza schineri is recorded in Britain and elesewhere forming twig galls on Populus.

The agromyzid Phytobia cambii feeds in the cambium of Salix and Populus in Britain and also Alnus, Betula and Carpinus elsewhere.

Elsewhere the agromyzids Agromyza albitarsis, Aulagromyza populi, Aulagromyza populicola and Aulagromyza tremulae are recorded mining Populus.

Twenty-One non-Diptera miner is recorded on Populus in Britain (see below).

Elsewhere four additional British non-Diptera miners are recorded on Populus (see below).

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

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 at least 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 tisses via a hole cut in the epidermis. Mine does not contain frass (Coleophora species)

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1b > Leaf-miner or galler, but not a case-bearer: The larva lives mainly inside the mine. Mine usually contains frass. In later instars the larva may live sandwiched between two more or less circular sections cut from the leaf e.g. Incurvaria species.

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2 > Leaf-miner and case-bearer: The larva feeds by inserting its head into small mines it creates on the leaves of birch, elm, alder, or hazel. Occasionally it is found feeding on other trees, or on herbaceous plants onto which it has accidentally Fallén. It forms two cases during its larval life. The first case is initially curved, smooth, laterally compressed with a bivalved anal opening, and about 2 mm long in September. During October it feeds, and adds a few rough collars of larval material around the oral opening. After hibernation, it feeds again in April and early May, adding more protruding collars until they equal or exceed the original smooth part of the case. At the same time, it expands the case girth by the creation of a silk gusset ventrally. The second case, 6 or 7 mm long, is formed in May, leaving the vacated first case attached to its last feeding mine. The new case is tubular with a trivalved crimp at the anal opening. The dorsum is formed from the edge of the leaf from which the case was cut. This results in a more or less serrated dorsal keel, depending on the plant species and the individual piece of leaf used. Considerable variation in the degree of serration can be found, even among specimens off the same tree. The case colour varies with food plant, from yellowish brown on birch, darkening through elm and hazel to dark brown on alder (UKMoths). The strongly curved young case is is a composite leaf case, the adult case is a tubular leaf case. The adult case is bivalved, about 7 mm in length; the mouth angle is around 30°. The case is straw coloured and almost always has a toothed dorsal keel (remnant of the margin of the leaf from which the case was cut). Neither larvae or cases of C. coracipennella, prunifoliae, serratela and spinella can be separated; from serratella (Bladmineerders van Europa).

Recorded on Alnus, Betula, Corylus and Ulmus, but not yet on Populus, in Britain plus Carpinus, Mespilus, Ostrya, Hippophae, Ribes, Myrica, Forsythia, Amelanchier, Chaenomeles, Cotoneaster, Crataegus, Cydonia, Eriobotrya, Malus, Prunus, Sorbus , Spiraea, Populus and Salixelsewhere. This is probably the commonest species of British coleophorid, and is found throughout the British Isles. Widespread in continental Europe.

Coleophora serratella (Linnaeus 1761) [Lepidoptera: Coleophoridae].

3a > Gall and Leaf-miner: A gall in petiole, later mine in leaf-blade, in 'green island' (British leafminers).

The egg is placed on the petiole, about a cm below the base of the leaf; often one egg at either side. The larva first bores in the distal part of the petiole, that shows a local swelling. When the larva reaches the leaf it makes an elongate triangular blotch between the leaf margin and the first side vein, or, less frequently, between midrib and side vein. Frass in two bands, parallel to the sides of the mine, created by the passage of the larva when it retreates into the petiole. The larva mainly feeds at night. Pupation external (Bladmineerders van Europa).

Mine of Ectoedemia turbidella on Populus canescens Image: David Manning (British leafminers)

Recorded on Populus in Britain and elsewhere. Widespread in Britain, particularly in the south. Widespread in continental Europe.

Ectoedemia turbidella (Zeller, 1848) [Lepidoptera: Nepticulidae].

3b > Leaf-miner: Initially a lower epidermal gallery which leads to a blotch at the leaf-edge. Subsequently creates two or three cones by folding the edge or tip of a leaf downwards (British leafminers). The mine begins with an unusually long lower-surface epidermal corridor that often follows the midrib for some distance, but finally turns towards the leaf margin, where a small blotch is made of up to 1 cm in diameter. The blotch initially is fully epidermal, but later the larva starts consuming parenchyma, silk is deposited, and the blotch begins to develop into a somewhat contracted tentiform mine. In the end the mine is vacated and the larva continues living freely under a leaf fold that has been fixed with silk, or in a leaf tip that has been turned into a cone. Pupation in a shiny cocoon at the underside of the leaf (Bladmineerders van Europa).

Recorded on Betula, Populus and Salix in Britain and Populus, Salix and Myrica elsewhere. Widespread in Britain, Ireland and continental Europe.

 

Caloptilia stigmatella (Fabricius, 1781) [Lepidoptera: Nepticulidae].

3c > Leaf-miner: Gall in petiole, later mine in leaf-blade, in 'green island' (British leafminers). Oviposition on the petiole, c. 1 cm below the base of the leaf. The larva begins its life as a borer in the petiole, causing it to swell somewhat. When the leaf disc is reached the larva makes an elongate blotch between the midrib and the first lateral vein. Frass in two stripes parallel to the sides of the mine. Pupation external. The larvae are active mainly at night, retreating into the petiole during daytime (Johansson et al., 1990a) (Bladmineerders van Europa).

Recorded on Populus in Britain and elsewhere. Locally distributed throughout mainland Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Ectoedemia argyropeza (Zeller, 1839) [Lepidoptera: Nepticulidae].

3d > Leaf-miner: The initial mine is in the leaf petiole and later the mines form green islands in the leaf (British leafminers). Oviposition in the petiole, c. a cm below the base of the leaf. The larva begins its life as a borer in the petiole, causing it to locally swell somewhat. Once the larva has reached the leaf disc it begins forming an elongate blotch between the leaf margin and the most lateral vein, or, more rarely, between the midrib and the first lateral vein. Frass in two stripes, parallel to the sides of the mine. Pupation external. The larvae feed only at night, retreating within the petiole at daytime. The larva can be lured into the mine by keeping the leaf in the dark for a while (Borkowski, 1969a). The arrangement of the frass in two stripes is the result of the regular movement of the larva (Bladmineerders van Europa).

Recorded on Populus in Britain and elsewhere. Recorded from South-east England including Ipswitch. Widespread in continental Europe.

 

Ectoedemia hannoverella (Glitz, 1872) [Lepidoptera: Nepticulidae].

3f > Leaf-miner: Transparent blotch, starting at the leaf margin, quickly turning brown. Frass in scattered grains (Bladmineerders van Europa).

Mine on Fenusella glaucopis on Populus canescens Image: Willem Ellis (Bladmineerders van Europa)

Recorded on Populus in Britain and elsewhere. Bedfordshire, Buckinghamshire and Hertfordshire in Britain. Widespread in continental Europe.

 

Fenusella glaucopis (Konow, 1907) [Hymenoptera: Tenthredinidae].

3g > Leaf-miner: transparent blotch, quickly turning brown, starting at the leaf margin. Frass in scattered grains (Bladmineerders van Europa). Care must be taken in identifying this miner as the mines of Fenusella glaucopis can appear similar (British leafminers).

Recorded on Populus in Britain and elsewhere. Recorded in Cambridgeshire in Britain and the Republic of Ireland. Widespread in Continental Europe.

 

Fenusella hortulana (Klug, 1818) [Hymenoptera: Tenthredinidae].

3h > Leaf-miner: The larvae feed on a range of deciduous trees, windowing leaves in autumn and eating the buds, catkins, young shoots and then spun leaves in the spring (UKMoths). Cocoon formed in soil or where the larva fed British leafminers.

Recorded on Corylus, Crataegus, Populus, Quercus and Salix in Britain and Alnus, Betula, Corylus, Crataegus, Populus, Quercus and Salix elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Gypsonoma dealbana (Frölich, 1828) [Lepidoptera: Tortricidae].

3i > Leaf-miner: Large, deep, upper-surface blotch that starts at the leaf margin, without an accumulation of frass. Around the oviposition site the leaf turns reddish brown. Frass in scattered grains, but towards the end of the larval period an opening is made in the mine, and both frass and exuvia are ejected. About that time the mined leave is shed, and the larva makes a disk-shaped cocoon within the mine, in which it diapauses until the following spring (Bladmineerders van Europa).

Recorded on Populus in Britain and elsewhere. Distribution in Britain unknown. Widespread in continental Europe.

 

Heterarthrus ochropoda (Klug, 1818) [Hymenoptera: Tenthredinidae].

3j > Leaf-miner: Almost round, brown to brownish black, upper surface, very opaque blotch, about 1 cm in diameter, without an initial corridor. Upper epidermis leathery in colour. Often several mines in a leaf. All frass as a tar-like film on the floor of the mine (Bladmineerders van Europa). Larva without abdominal legs.

Recorded on Populus in Britain and elsewhere. Recorded from East Kent and East Sussex and Hants in Britain. Widespread in continental Europe.

 

Isochnus sequensi (Stierlin, 1894) (Stierlin, 1894) [Coleoptera: Curculionidae]..

3k > Leaf-miner: Eggs are deposited on the upperside of the leaf, mostly in groups of 5-10, less often singly, generally along a vein; the empty shells are flat and shining. The snow-white larvae form large, upper-surface blotches in which considerable larvae may be present, also mines may coalesce. Pupation is external; exit slit in upper epidermis (Bladmineerders van Europa).

Recorded on Populus in Britain and Populus and Salix elsewhere. Britain including East Ross, Easterness and Elgin. Widespread in continenetal Europe.

 

Leucoptera sinuella (Reutti, 1853) [Lepidoptera: Lyonetiidae].

3l > Leaf-miner: A 'snail-trail'-like mine on the upper surface, long and sinuous, without any visible frass. The mine can sometimes cover most of the leaf (British leafminers). Very long, broad, epidermal corridor that winds in dense loops over the upperside of the leaf without crossing itself. Frass in a continuous, extremely vague central line. The mine ends at the leaf margin, where the corridor is slightly widened, and in which some silk is deposited. When this dries the the leaf margin somewhat folds over this pupal chamber, since it is here that pupation takes place.The mine has a strong resemblance to the trail of dried mucus left by a small snail, which has given the mine its Dutch name of snail-trail mine (Bladmineerders van Europa).

Recorded on Populus in Britain and elsewhere. Fairly common in most of England, becoming scarcer further north. Widespread in continental Europe.

 

Phyllocnistis unipunctella (Stephens, 1834) [Lepidoptera: Gracillariidae].

3m > Leaf-miner: A 'snail-trail'-like mine on the upper surface, long and sinuous, with a dark central frass trail, ending at the leaf margin (British leafminers). Very long, rather broad, strictly epidermal, corridor that curves in dense loops over the leaf upperside, without ever crossing itself. Frass in a vague continuous central line. The gallery ends upon the leaf margin, where it widens a little, while the leaf margin folds over somewhat. Here pupation takes place, not in a cocoon (Bladmineerders van Europa). Under a silk membrane on the margin of leaf (British leafminers).

Recorded on Populus in Britain and elsewhere. Southern England. Widespread in continental Europe.

Phyllocnistis xenia M. Hering, 1936 [Lepidoptera: Gracillariidae].

3n > Leaf-miner: An underside mine, with few creases and causing little leaf distortion. Some mottling of the upper leaf surface may be caused (British leafminers). Oval, lower-surface tentiform mine. The lower epidermis has no recognisable folds, and in fact the mine is barely visible in the felty underside of the leaf. Frass heaped in an angle of the mine. Pupa in a barely recognisable flimsy cocoon (Bladmineerders van Europa).

Recorded on Populus in Britain and elsewhere. Southern England. Widespread in continental Europe.

 

Phyllonorycter comparella (Duponchel, 1843) [Lepidoptera: Gracillariidae]..

3o > Leaf-miner: The lower surface of the mine can have small creases and appear reddish (British leafminers). Lower surface oval tentiform mine, without a fixed position on the leaf. The mine is yellowish, sometimes tinged with red; black when old. Frass stacked in one corner of the mine, the almost black pupa, in a very flimsy cocoon, in the other (Bladmineerders van Europa).

Recorded on Populus in Britain and elsewhere. A rare miner in the UK, discovered in 1977 in Gloucester and subsequently recorded from Hereford and Worcester. Widespread in continental Europe.

 

Phyllonorycter sagitella (Bjerkander, 1790) [Lepidoptera: Gracillariidae].

3p > Leaf-miner: The larvae feed in a blotch on the underside of a leaf of sallow, causing the leaf edge to curl under when at the edge (UKMoths). Fairly small, lower-surface, tentiform mine, often toching the leaf margin. The reddish brown pupa in a flimsy, whitish of very pale yellowish cocoon; possibly the cocoon sometimes is missing altogether. Frass packed in a corner of the mine (Bladmineerders van Europa). Cannot be separated (without opening mine or breeding moths) from mines of other sallow-feeding species (British leafminers).

Recorded on Populus in Britain and Populus and Salix elsewhere. Throughout the British Isles. Also recorded in the Republic of Ireland. Widespread in continental Europe.

 

Phyllonorycter salicicolella (Sircom, 1848) [Lepidoptera: Gracillariidae]..

3q > Leaf-miner: The mine is underside, strongly creased and contracted causing leaf-edge to fold down (British leafminers, as Phyllonorycter salictella viminiella). Rather large, lower-surface tenntiform mine, generally against the leaf margin, often low in the leaf. Lower epidermis strongly folded; the mine is strongly contracted, causing the leaf margin to fold tube-like over the mine. All frass packed in a corner of the mine (Bladmineerders van Europa). Pupa reddish brown, in a light brown cocoon without frass.

Mine of Phyllonorycter salictella Image: Ian Kimber (British leafminers)

Recorded on Populus and Salix in Britain and Salix elsewhere. Throughout England and Wales and into southern Scotland and there are scattered records from Ireland and northern Scotland. Widespread in continental Europe.

 

Phyllonorycter salictella (Zeller, 1846) [Lepidoptera: Gracillariidae]..

3r > Leaf-miner: Generally small, upper-surface, pear-shaped mines, half of their surface stuffed with frass. In the frass-free part an oval, flattened larva. Often several mines in a leaf. Prior to oviposition the larvae eat, a large number of tiny holes in the leaves (Bladmineerders van Europa). Larva without abdominal legs.

Recorded on Betula, Myrica, Populus and Salix in Britain and elsewhere. Widespread in Britain, Ireland and continental Europe.

 

Rhamphus pulicarius (Herbst, 1795) [Coleoptera: Curculionidae].

3s > Leaf-miner: The initial gallery has clear margins, with broken linear frass. The later mine is a blotch formed by many turns (British leafminers). Oviposition at the leaf upper surface. Mine a densely winding corridor, later sections strongly widened, almost forming a secondary blotch. Frass in a more or less continuous central band that, even in the narrow initial part, never completely fills the corridor (Bladmineerders van Europa).

Recorded on Populus in Britain and elsewhere. Widespread in England, Scotland and continental Europe.

 

Stigmella assimilella (Zeller, 1848) [Lepidoptera: Nepticulidae].

3t > Leaf-miner: A gallery leading to a blotch (British leafminers). Egg either at upper- or lowerside of the leaf. The mine is a corridor; the first part is rather straight and narrow, and often follows a vein for some length; the second part is much broader, sometimes almost a blotch. In the first part of the mine the frass lies in a more or less uninterrupted central line that does not occupy the full with of the gallery; in the second part the frass pattern is very variable, ranging from a narrow central line to a broad band (Bladmineerders van Europa).

Recorded on Populus in Britain and elsewhere. Widespread in England. Also recorded from Scotland, Wales and the Republic of Ireland. Widespread in continental Europe.

 

Stigmella trimaculella (Haworth, 1828) [Lepidoptera: Nepticulidae].

3u > Leaf-miner: All western European Zeugophora miners make large, blackish brown, upper-surface blotch. Oviposition at the leaf underside, in a small pit, that is covered by secretion. These oviposition marks remain visible as small, transparent points. The larvae of Zeugophora species are yellow, flattened, and legless. They live communal, and leave the mine through an upper-surface exit slit (Bladmineerders van Europa).

Recorded on Populus in Britain and Populus and Salix elsewhere. Widespread in England and continental Europe.

 

Zeugophora flavicollis (Marsham, 1802) [Coleoptera: Chrysomelidae].

3v > Leaf-miner: All western European Zeugophora make large, blackish brown, upper-surface blotch. Oviposition at the leaf underside, in a small pit, that is covered by secretion. These oviposition marks remain visible as small, transparent points. The larvae of Zeugophora species are yellow, flattened, and legless. They live communal, and leave the mine through an upper-surface exit slit (Bladmineerders van Europa).

Recorded on Populus in Britain and Populus and ? Salix elsewhere. Widespread in England and contonental Europe.

Zeugophora subspinosa (Fabricius, 1781) [Coleoptera: Chrysomelidae].

3w > Leaf-miner: All western European Zeugophora make large, blackish brown, upper-surface blotch. Oviposition at the leaf underside, in a small pit, that is covered by secretion. These oviposition marks remain visible as small, transparent points. The larvae of Zeugophora species are yellow, flattened, and legless. They live communal, and leave the mine through an upper-surface exit slit (Bladmineerders van Europa).

Recorded on Populus in Britain and elsewhere. Apparently a northern species, recorded in East Ross, Easterness, Elgin, South Aberdeen and West Sutherland Widespread in continental Europe.

 

Zeugophora turneri Power, 1863 [Coleoptera: Chrysomelidae].

3x > Leaf-miner: Full depth, broad, transparent, brown, corridor that descends from the leaf tip along tje leaf margin. Frass in a stripe along the outer side of the mine. The mine ends in a round excision (Bladmineerders van Europa). Larva without abdominal legs.

Recorded on Salix, but not yet on Populus, in Britain and Populus and Salix elsewhere. North Hants and West Suffolk. Widespread in continental Europe.

 

Tachyerges decoratus (Germar, 1821) [Coleoptera: Curculionidae].

3y > Leaf-miner: A large, full depth transparent light brown blotch that expands irrespective of the leaf venation. Mine mostly in the distal half of the leaf, may eventually occupy half of its surface. The mine often tears in, and the leaf tip is disfigured (Bladmineerders van Europa). Larva without abdominal legs. The larva eventually pupates in a globular cocoon within the mine (Bladmineerders van Europa).

Recorded on Salix in Briain and Populus and Salix elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Tachyerges salicis (Linnaeus, 1758) [Coleoptera: Curculionidae].

3z > Leaf-miner: Oviposition in the base of the midrib, without giving rise to an oviposition scar. The larva initially bores inside the midrib. Later it leaves the midrib, forming a broad corridor in the blade, that widens into a blotch. Finally the legless larva pupates in a globular cocoon inside the mine. Because the mine develops at a time that the leaf is fully developed, mined leaves are not disfigured (Bladmineerders van Europa).

Recorded on Betula, Corylus and Salix, but not yet on Populus, in Britain and Alnus, Betula, Corylus, ? Populus and Salix elsewhere. Widespread in Britain and continental Europe.