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TUSSILAGO. Colt's-foot. [Asteraceae] |
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Colt's-foot (T. farfara) is the only species of Tussilago recorded in Britain. Three Diptera miners, the agromyzid Phytomyza tussilaginis and the tephritids Acidia cognata and Trypeta zoe are recorded on Tussilago in Britain. The polyphagous agromyzid Liriomyza huidobrensis has been recorded in quarantine in Britain (Dom Collins (pers. comm.)). Elsewhere the agromyzids Liriomyza strigata, Liriomyza huidobrensis and Phytomyza tussilaginis, and the tephritids Acidia cognata, Stemonocera cornuta and Trypeta zoe are recorded mining Tussilago. Two non-Diptera miners are recorded on Tussilago in Britain (see below). The pterophorid Platyptilia gonodactyla is recorded as a stem and flower feeder on Tussilago in Britain. Elsewhere one British non-Diptera miner is recorded on Tussilago (see below). |
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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). 1 > An upper surface corridor mine, becoming strongly broadened and blotch-like. The mine can occupy a considerable part of a small leaf. Mines frequently merge, and then accommodate several larvae. Pupation external, in soil. Puparium yellow
Acidia cognata (Wiedemann, 1817) [Diptera: Tephritidae]. -> Corridor mine following the mid-rib, with lateral offshoots. Puparium yellow
Trypeta zoe Meigen, 1826 [Diptera: Tephritidae]. -> A long linear greenish-white mine which can conspicuously widen at end, with frass in separate grains. Puparium black
Phytomyza tussilaginis Hendel, 1925 [Diptera: Agromyzidae]. |
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Key
for the identification of the mines of British
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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).
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1a > 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).
Cnephasia incertana (Treitschke, 1835) [Lepidoptera: Tortricidae] |
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1b > The mine is brownish and extends along the midrib, sometimes branching (British leafminers). Oviposition on top of the midrib. Immediately after emergence the larva gnaws a cavity in the midrib, and from there an irregular blotch is made adjacent to the midrib. The larva continues living in the midrib that is gradully hollowed out, making from there broad, brownish, full depth excursions in the blade. The mine contains much frass; most of it is concentrated in the area immediately bordering the midrib. Older, no longer occupied parts of the mine often split open. Mines mainly on the lower leaves. The slender larvae move surprisingly fast upon disturbance; when they rest (in daytime) they lie lengthwise in the hollowed midrib. Pupation outside the mine (Bladmineerders van Europa).
Scrobipalpa acuminatella (Sircom, 1850) [Lepidoptera: Incurvariidae] |
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| 1c > The larva mines the leaves creating an irregular blotch (UKMoths). Initially a branching corridor, later more an elongate upper-surface blotch from the leaf base to the leaf margin, finally occupying a good part of the leaf. Most frass is deposited in one section of the mine, forming a crust below which the very agile larvae can retreat (Bladmineerders van Europa). | ||
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Scrobipalpula tussilaginis (Stainton, 1867) [Lepidoptera: Gelechiidae] . |
| Last updated 02-Feb-2012 Brian Pitkin |  |
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