Twenty one species of Bromus are recorded in Britain. These include the native Meadow Brome (B. commutatus), Soft-brome (B. hordeaceus), with five subspecies, Smooth Brome (B. racemosus) and Interrupted Brome (B. interruptus).

Seven Diptera miners, the agromyzids Agromyza albipennis, Agromyza bromi, Agromyza mobilis, Agromyza rondensis, Cerodontha incisa, Cerodontha pygmaea and Liriomyza flaveola, are recorded on Bromus in Britain. Miners on grasses should, where possible, be reared to confirm their identity.

Elsewhere the agromyzids Agromyza bromi, Agromyza intermittens, Agromyza mobilis, Agromyza nigrella, Agromyza rondensis, Cerodontha flavocingulata, Cerodontha incisa, Cerodontha muscina, Chromatomyia fuscula, Chromatomyia nigra and Liriomyza flaveola and the ephydrid Hydrellia griseola are recorded mining Bromus.

One non-Diptera miner, Elachista megerlella, is recorded on Bromus in Britain (see below).

Elsewhere five additional British non-Diptera miners are recorded on Bromus (see below).

The coleophorid Coleophora lixella is recorded as a seed-feeder on Bromus elsewhere.

A key to the European miners, based on characteristics of the mines, immature stages and where relevant the larval cases, recorded on Anisantha, Bromopsis and Bromus is provided in Bladmineerders van Europa. This includes Agromyza intermittens, Agromyza albipennis, Agromyza rondensis, Agromyza bromi, Agromyza nigrella and Agromyza mobilis, Cerodontha muscina, Chromatomyia nigra, Chromatomyia fuscula, Cerodontha incisa, Cerodontha pygmaea, Liriomyza flaveola and Cerodontha flavocingulata, Coleophora onopordiella, Coleophora lixella, Hydrellia griseola, Coleophora ornatipennella, Elachista albifrontella, Elachista argentella, Elachista atricomella, Elachista cingillella, Elachista elegans, Elachista herrichii, Elachista lastrella, Elachista luticomella, Elachista maculicerusella, Elachista obliquella, Elachista nobilella, Elachista sicula, Elachista subnigrella, but not Coleophora tricolor or Elachista megerlella. The mines of Elachista spp. on Bromus are insufficiently diagnostic and the larvae of most are not well known. A key cannot be made.

N.B. The key to mines below includes mines recorded on Bromopsis and Bromus (Poaceae).

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

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: The larva mines from the grass tip downwards and the mine occupies half or the whole of the leaf blade width. A whitish blotch is formed with characteristic narrow streaks of frass (British leafminers). Full depth blotch, slightly inflated, descending from the leaf tip, occupying half or the entire width of the blade. The larva may move and make a new mine elsewhere. In the latter case the mines are fairly short; otherwise an entire blade may be mined out. Frass in a some narrow greyish brown streaks. Pupation outside the mine (Bladmineerders van Europa).

Recorded on Dactylis, Deschampsia and Holcus, but not yet on Bromus, in Britain plus Luzula, Agrostis, Alopecurus, Arrhenatherum, Avena, Avenula, Brachypodium, Bromus, Calamagrostis, Elymus, Festuca Koeleria, Phalaris, Phleum, Poa, Trisetum and Triticum elsewhere. Widespread in Britain, Ireland and continental Europe.

 

Elachista albifrontella (Hübner, 1817) [Lepidoptera: Elachistidae].

1b > Leaf-miner: A small narrow mine on a wide variety of grasses. In the spring the larva changes leaves and mines tip downwards. The mine fills the leaf width. The frass is packed in the top of the mine (British leafminers). In autumn the larva makes a narrow corridor a few cm in length, in which it hibernates. In March it moves to a new leaf. Here a transparent, full depth mine is made that descends from the leaf tip, and occupies the entire width of the blade. Most frass is concentrated in the oldest, highest, part of the mine. The larva may leave its mine and restart elsewhere. Pupation outside the mine (Bladmineerders van Europa)

Mine of Elachista argentella on Dactylis glomerata Image: Ben Smart (British leafminers)

Recorded on Dactylis glomerata, but not yet on Bromus, in Britain. Recorded on numerous grasses including Bromus elsewhere. Widespread in Britain and continental Europe. Also recorded in the Republic of Ireland.

Elachista argentella (Clerck, 1759) [Lepidoptera: Elachistidae].

1c > Leaf-miner: Like related species, the larva mines blades of grass, in this case usually Cock's-foot, forming a thin whitish mine (UKMoths). The larva begins in autumn the making of a long, narrow, corridor with a fine central line of grey frass. The corridor is straight or lightly wavy, and descends into the leaf sheath, or even into the stem or rootstock. The larva regularly leaves the mine to begin making a new one. Pupation external (Bladmineerders van Europa).

Recorded on Dactylis, but not yet on Bromus, in Britain and Bromus, Carex, Dactylis, Melica and Milium elsewhere. Widespread in Britain, Ireland and continental Europe.

 

Elachista atricomella Stainton, 1849 [Lepidoptera: Elachistidae].

1d > Leaf-miner: Long, flat, whitish, relatively broad corridor descending from the leaf tip. Frass irregularly scattered. The larva may make several mines during its lifetime. Pupation outside the mine (Bladmineerders van Europa).

Recorded on Dactylis, Holcus and Poa, but not yet on Bromus, in Britain plus Agrostis, Bromus, Festuca, Holcus, Koeleria, Trisetum and Triticum elsewhere. Widespread and reasonably common throughout much of the British Isles except the very far north. Widespread in continental Europe.

 

Elachista freyerella (Hübner, 1825) [Lepidoptera: Elachistidae].

1e > Leaf-miner: Larva makes a large whitish blotch and mines the leaf downwards. The frass tends to be deposited in the upper part of the mine (British leafminers). Oviposition usually not far from the leaf tip. From there descends an irregular blotch mine. Hering (1957a) describes the mine as flat and quite shallow, giving it a greenish, rather than whitish appearance. Frass initially in the oldest, upper part of the mine, later in strings. The larva can leave its mine and restart elsewhere. Normally only one larva per mine, but sometimes two or even three mines in a leaf. Pupation outside the mine (Bladmineerders van Europa).

Recorded on Dactylis, Phalaris, Phragmites and Poa, but not yet on Bromus, in Britain plus Agrostis, Alopecurus, Arrhenatherum, Brachypodium, Calamagrostis, Elymus, Festuca, Holcus, Trisetum and Triticum eelsewhere. Widely distributed in Britain, Ireland and continental Europe.

 

Elachista maculicerusella (Bruand, 1859) [Lepidoptera: Elachistidae].