SYMPHYTUM. Comfreys. [Boraginaceae]

Nine species of Symphytum are recorded in Britain. These include the native Tuberous Comfrey (S. tuberosum) and Common Comfrey (S. officinale).

Four Diptera miners, the agromyzids Agromyza abiens, Agromyza ferruginosa, Agromyza myosotidis and Phytomyza medicaginis, are recorded on Symphytum in Britain and two of these, Agromyza abiens and Agromyza myosotidis also occurs on Pentaglottis.

The agromyzid Melanagromyza symphyti bores the stems or leaf stalks of Symphytum in Britain.

Elsewhere the agromyzids Agromyza abiens, Agromyza ferruginosa, Agromyza myosotidis, Chromatomyia horticola and Phytomyza spondyli are recorded mining Symphytum.

One non-Diptera leaf-miner, Dialectica imperialella, is recorded on Symphytum in Britain (see below).

Elsewhere two additional British non-Diptera miners are recorded on Symphytum (see below).

N.B. The key to mines below includes mines recorded on Pentaglottis and Symphytum (Boraginaceae).

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

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, 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 in a distinctive case made from hairy leaf fragments of the foodplant (UKMoths). The young larva feeds on the developing seeds and hibernates in its first case which is made of the tip of a petal. After hibernation it makes a hoary, laterally flattened composite leaf case (resembling a willow catkin). Full depth mines are made at the margin of the leaves, that thereby look peculiarly damaged. Mouth angle 70° (Bladmineerders van Europa). Initially forms a blotch mine, in the centre of a leaf, which it excises for its initial case. In the spring it repeatedly extends its case and it resembles a jagged catkin of willow. The larva may wander from its foodplant and attach to other plants or fences etc (British leafminers).

Recorded on Anchusa, Echium and Pentaglottis, but not yet on Symphytum in Britain and Anchusa, Cynoglossum, Echium, Lithospermum, Myosotis, Nonea, Pentaglottis, Pulmonaria and Symphytum elsewhere. South-east England and East Anglia, with scattered records elsewhere including East Kent and East Sussex. Widespread in continental Europe.

Coleophora pennella (Denis and Schiffermüller, 1775) [Lepidoptera: Coleophoridae]

3a > 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 (Bladmineerders van Europa).

Recorded on numerous genera and species of several plant families, but not yet on Symphytum, in Britain. Recorded on numerous genera and species of several plant families, including Symphytum, elsewhere. Widespread in Britain and continental Europe. Also recorded from the Channel Is.

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

3b > The initial gallery is soon absorbed into a blotch. The blotch is squarish as the larva eats through the leaf parenchyma to the upper epidermis. the blotch turns brown and care must be taken to distinguish these mines from diptera - which can form blackish blotches (British leafminers). The larva makes a small, lower-surface spiralling corridor that soon gives way to a blotch that overuns the previous work. Gradually the mine becomes deeper, and finally is locally full depth. Only then the mine is apparent from above as some disconnected brownish spots. On the underside the mine is larger, membranous. The frass initially is in strings, but later it becomes a network of thin threads. Pupation usually is outside the mine (Bladmineerders van Europa).

Recorded on Pulmonaria and Symphytum in Britain and Lithospermum, Pulmonaria and Symphytum elsewhere. Britain including Cambridge and Hunts. Widespread in continental Europe.

Dialectica imperialella (Zeller, 1847) [Lepidoptera: Gracillariidae]