Mentha [Lamiaceae]

MENTHA. Mints. [Lamiaceae]

Seven species of Mentha are recorded in Britain. These included the native Water Mint (M. aquatica), Corn Mint (M. arvensis), Pennyroyal (M. pulegium) and Round-leaved Mint (M. suaveolens).

Pennyroyal (M. pulegium) is protected under Schedule 8 of the Wildlife and Countryside Act, 1981 and in Northern Ireland under Schedule 8 of the Wildlife (Northern Ireland) Order, 1985.

Four Diptera miners, the agromyzids Chromatomyia horticola, Phytomyza obscura, Phytomyza petoei and Phytomyza tetrasticha, are recorded on Mentha in Britain.

The agromyzid Napomyza scrophulariae is recorded feeding in both seed heads and stems of Digitalis pupurea and possibly Scrophularia nodosa, Verbascum and Mentha in Britain.

Elsewhere the agromyzids Amauromyza labiatarum, Amauromyza lamii, Chromatomyia horticola, Phytomyza petoei and Phytomyza tetrasticha are recorded mining Mentha.

One non-Diptera leaf-miner is recorded on Mentha in Britain (see below).

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

Water Mint - Mentha arvensis Image: Brian Pitkin

Water Mint
Mentha aquatica

Key for the identification of the mines of British Diptera recorded on
Mentha

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).

1a > Leaf-miner: Mine linear, whitish, both upper and lower surface. Pupation internal, at the end of the mine with the anterior spiracles projecting through the epidermis (Spencer, 1976: 433). Upper-surface, less often lower-surface corridor. Frass in isolated grains. Pupation within the mine, in a, usually lower-surface, pupal chamber (Bladmineerders van Europa). A long whitish upper surface corridor, which eventually goes lower surface (British leafminers).

Two highly polyphagous species of Chromatomyia, with indistinguishable mines, have been recorded in Britain. These are syngenesiae (Hardy) and horticola (Goureau) which can only be distinguished by the male genitalia. Both are polyphagous and widespread in Britain and elsewhere, although syngenesiae is almost entirely restricted to Asteraceae (see also 'atricornis').

Chromatomyia horticola is recorded on 55 plant genera in 19 families in Britain including Mentha in Britain.

Chromatomya syngenesiae is recorded in Britain on 27 plant genera in the family Asteraceae and many more genera elsewhere, but not yet on Mentha in Britain.

Chromatomyia horticola (Goureau, 1851) [Diptera: Agromyzidae].
OR
Chromatomyia syngenesiae Hardy, 1849 [Diptera: Agromyzidae].

1b > Mine beginning with a small spiral, later developing into a greenish blotch, frequently at leaf margin, brown when old. Pupation internal or external. Puparium yellowish brown in summer generation, deep black in winter generation

On Mentha aquatica, Mentha longifolia and Mentha suaveolens in Britain and additional species of Mentha elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Phytomyza tetrasticha Hendel, 1927 [Diptera: Agromyzidae].

1c > Mine beginning with a small spiral, later developing into a greenish blotch, brown when old. Pupation frequently in mine

On Clinopodium, Mentha and Nepeta in Britain and Clinopodium and Satureja elsewhere. Doubtfully recorded from Oxford in Britain. Widespread in continental Europe.

Phytomyza obscura Hendel, 1920 [Diptera: Agromyzidae].

1d > An irregularly linear mine which may become a secondary blotch. Pupation normally external, but not infrequently the puparium remains in the leaf at the prepared exit slit. Puparium yellowish brown

On Mentha in Britain and elsewhere. Probably not uncommon in Britain. Widespread in continental Europe.

Phytomyza petoei Hering, 1924 [Diptera: Agromyzidae].

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

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: Blotch mines reaching the edge of the leaf, initially pale green turning brownish white, are caused by the larva feeding on the underside of a leaf (UKMoths). The fully developed case is slender, shining black brown, about 9 mm long. Towards the end a narrow, transparent yellowish ventral keel. Mouth angle 50-60°. Cases on the leaf underside (Bladmineerders van Europa).

Recorded on Calamintha, Clinopodium, Glechoma, ? Lycopus, Mentha, Nepeta, Origanum, Prunella, Salvia, Stachys and Thymus in Britain plus Melissa, Melittis and Satureja but not Calamintha elsewhere. Throughout England and Wales and a few places in Scotland. Widespread in continental Europe.

Coleophora albitarsella Zeller, 1849 [Lepidoptera: Coleophoridae]

1b > Leaf miner, but not a case bearer

2a > Leaf-miner: Young larvae make small, brown, full depth blotch mines without frass in the young leaves, from within the protection of a spinning. Later they cause upper-surface window feeding, while hidden among spun leaves (Bladmineerders van Europa).

Recorded on Thymus, but not yet on Mentha, in Britain and Mentha, Thymus and Satureja elsewhere. Widespread in Britain and continental Europe. Also recorded in Ireland.

Scrobipalpa artemisiella (Treitschke, 1833) [Lepidoptera: Gelechiidae]

2b > Leaf-miner: Upper-surface, transparent blotch that begins at the leaf margin, generally at the underside of the leaf. Oviposition site covered by a shining brown drop of hardened secretion. Frass in grains or thread fragments (Bladmineerders van Europa). Larva without abdominal legs.

Recorded on Glechoma, but not yet on Mentha, in Britain and ? Clinopodium, Glechoma, ? Marrubium, Mentha, ? Nepeta and ? Stachys elsewhere. Widespread in Britain and continental Europe.

Trachys scrobiculatus Kiesenwetter, 1857 [Coleoptera: Buprestidae]


	Last updated 01-Feb-2012 Brian Pitkin