MEDICAGO. Medicks. [Fabaceae]

Thirty species of Medicago are recorded in Britain. These include the native Spotted Medick (M. arabica), Black Medick (M. lupulina), Bur Medick (M. minima), Toothed Medick (M. polymorpha), Sand Lucerne (M. sativa varia) and Sickle Medick (M. sativa falcata).

Medicago sativa subsp. varia is treated as Medicago sativa nothossp. varia by Stace (2010).

Six Diptera miners, the agromyzids Agromyza frontella, Agromyza nana, Chromatomyia horticola, Liriomyza congesta and Ophiomyia curvipalpis, are recorded or tentatively recorded on Medicago in Britain.

The British drosophilid Scaptomyza graminum is recorded on Medicago by Chandler (1978), but it is not clear whether the host association is British or Foreign.

The agromyzids Liriomyza huidobrensis, Liriomyza sativae and Liriomyza trifolii, pest species of ornamental and vegetable crops occasionally intercepted at UK points of entry, are recorded on Medicago.

Liriomyza huidobrensis and Liriomyza trifolii, have been found under glass in England and Wales. All populations have been and continue to be eradicated.

Elsewhere the agromyzids Agromyza frontella, Agromyza nana, Chromatomyia horticola, Liriomyza bryoniae, Liriomyza congesta, Liriomyza huidobrensis, Liriomyza sativae, Liromyza strigata, Liriomyza trifolii and possibly Ophiomyia curvipalpis, and the drosphilids Scaptomyza flava and Scaptomyza graminum are recorded mining Medicago.

Three non-Diptera miners are recorded on Medicago in Britain ( see below).

Elsewhere one additional British non-Diptera miner, Coleophora discordella, is possibly recorded on Medicago.

N.B. The key to mines below includes mines recorded on Lotus, on Medicago and Trifolium (Fabaceae).

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

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 initial mine is like that of a nepticulid. The case is made form excised leaf portions, which are added to the oral end, leading to the ringed appearance. The larva causes the leaf to have white blotches. Identification cannot be made on these alone as similar blotches can be made by early instar larvae of the Common Blue butterfly (Polyommatus icarus) (British leafminers). Oviposition at the leaf underside, mostly in a vein axil. The larva begins by making a narrow winding corridor with much frass in a broad central line. The corridor reminds that of a nepticulid (but the egg has a finely reticulate surface, unlike the smooth nepticulid egg.) In the end the corridor widens into an oval blotch, usually close to the leaf margin, out of which the first case is made. The full grown larva in a greyish brown composite leaf case of about 6 mm, attached to the underside of a leaf. The oldest quarter of the case is bivalved, laterally compressed, and is at an angle of 70° with the anterior part of the case. The mouth angle is around 40° (Bladmineerders van Europa).

Recorded on Lotus, but not yet on Medicago, in Britain and ? Astragalus, ? Dorycnium, Lotus, ? Medicago and ? Oxytropis elsewhere. Widespread in Britain, Ireland and continental Europe.

? Coleophora discordella Zeller, 1849.

3a > Leaf-miner: The first generation initially forms an unmistakable leaf-mine on Anthyllis vulneraria, but the second generation feeds on the flowers. Feeding signs on other plants vary in appearance. Larvae can move between sewn leaves, and more than one larva may be found together (UKMoths). Larvae in a small full depth blotch, often with extensions. Frass concentrated in one corner of the mine. The mining activities may cause the leaf to roll inwards. Older larvae live free among spun leaves, but still they may make then full depth mines by feeding on the leaf tissue from a small opening (Bladmineerders van Europa).

Recorded on Anthyllis, Medicago, Onobrychis, Ononis and Trifolium in Britain and Anthyllis, Chamaecytisus, Coronilla, Cysisus, Dorycnium, Galega, Glycine, Hymenocarpus, Lathyrus , Lotus, Medicago, Melilotus, Onobrychis, Ononis, Ornithopus, Oxytropis, Phaseolus, Psoralea, Trifolium, Trigonella and Vicia elsewhere. Britain including the Channel Is. and Northern Ireland. Also recorded in the Republic of Ireland. Widespread in continental Europe.

 

Aproaerema anthyllidella (Hübner, 1813) [Lepidoptera: Gelechiidae].

3b > 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].

3c > Leaf-miner: Lower surface tentiform mine that occupies only part of a leaflet. In full grown leaves the mine is strongly inflated and is largely hidden by the leaf. Unlike other species the entire leaflet is not mined out (Bladmineerders van Europa).

Recorded on Ononis and Trifolium, but not yet on Medicago, in Britain and Lathyrus, Medicago, Ononis, Trifolium and Vicia elsewhere. Britain including North Ebudes. Also recorded in the Republic of Ireland. Widespread in continental Europe.

 

Phyllonorycter insignitella (Zeller, 1846).

3d > Leaf-miner: The mine is underside, occupying the whole leaflet, which turns down at edges (British leafminers). Lower surface tentiform mine that occupies an entire leaflet; lower epidermis strongly folded. Fully developed mines are strongly inflated and the leaflet is so completely folded over the mine that the latter becomes practically invisible. In this stage the larva has consumed also all tissue in the roof of the mine, making the mine very conspicuous (Bladmineerders van Europa).

Recorded on Lathyrus, Medicago, Trifolium and Vicia in Britain and Lathyrus, Lotus, Medicago, Trifolium and Vicia elsewhere. England, Ireland and continental Europe.