The leaf and stem mines of British flies and other insects
 

(Coleoptera, Diptera, Hymenoptera and Lepidoptera)

by Brian Pitkin, Willem Ellis, Colin Plant and Rob Edmunds

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ARMORACIA. Horse-radish. [Brassicaceae]


One species of Armoracia, Horse-Radish (A. rusticana), is recorded in Britain.The BSBI provide a downloadable plant crib for Brassicaceae.

Four British miners are recorded on Armoracia.

A key to the European miners recorded on Armoracia is provided in Bladmineerders van Europa.



Key for the identification of the known mines of British
insects (Diptera and non-Diptera) recorded on Armoracia


1a > Leaf and stem mine: Oviposition takes place in the leaf blade where a short mine is formed until the larva reaches the nearest vein which is then followed downwards, with the main feeding occurring in the mid-rib, petiole, or in young plants, also in the stem (Spencer, 1976: 490). Pupation either internal or external.

The mine begins somewhere in the leaf, generally at the lower surface, not far from the leaf margin. From there a corridor runs randomly, until it hits upon a vein. The corridor then follows this vein until it reaches the midrib. Then the larva starts to bore into the midrib, and may descend into the petiole or even the stem. Pupation may take place either within or outside the mine (Bladmineerders van Europa).

On Brassica, but not yet on Armoracia, in Britain and additional genera of Brassicaceae, including Armoracia, elsewhere. Widespread but only recorded from Warwick, Dunbarton and East Lothian in Britain. Also recorded in the Republic of Ireland, continental Europe, Egypt, Canada and the U.S.A.

Phytomyza rufipes Meigen, 1830 [Diptera: Agromyzidae].

1b > Leaf-miner: Corridor-blotch mine, normally dorsal; usually whitish; in small leaves it lies characteristically in the centre of the leaf often touching the petiole; in larger leaves it lies to one side of the mid-rib. Frass deposited in green clumps near the leaf margin. Pupation usually external, sometimes in a separate pupation mine.

Oviposition whitin the leaf, at the lower surface. The first part of the mine is a long, sometimes very long, corridor, that mostly will be overrun by the later developments. Generally this corridor is directed, frequently guided by a thick vein, to the midrib. The next section of the mine is large, irregular blotch overlying the basal section of the midrib. Locally large chunks of midrib tissue are consumed. From this central blotch excursions are made into the leaf blade: generally upper-surface, less often lower-surface and locally full-depth. In plants with narrow leaves, like Diplotaxis, the mine may occupy the entire width of the leaf. Often several larvae together in a mine. Frass blackish green, powdery, in clouds, sometimes along the sides of the corridors, later more in the periphery of the mine and in the end of extensions of the blotch, sometimes seemingly absent. (Often the frass can only be seen after the mine has been opened). Pupation generally in the ground, rarely within he leaf, in a short mine without frass. Hendel (1928a) described the biology, larva and puparium (Bladmineerders van Europa).

An initial narrow gallery then leads to a blotch on the midrib of the leaf (British leafminers).

Watch a video of a scaptomyzid fly larva on Arabidopsis on YouTube by mash92587.

Polyphagous. On numerous genera of Brassicaceae, Asteraceae, Papaveraceae, Resedaceae, Tropaeolaceae and Violaceae, including Alliaria, Barbarea, Brassica, Cheiranthus, Cochlearia, Coincyia, Conringia, Diplotaxis, Erysimum, ? Eruca, ? Hesperis. Lepidium, Matthiola, Raphanus, ? Rorippa and Sinapis, but not yet on Armoracia, in Britain and additional genera of these families, including Armoracia and Fabaceae elsewhere. Widespread, from Caithness in the north to Cornwall in the south of Britain. Also recorded in the Republic of Ireland, Europe, the East Palaearctic, Near East and Neartic Region.

Scaptomyza flava (Fallén, 1823) [Diptera: Drosophilidae].

1c > Leaf-miner: A short, irregular, linear upper surface mine on any part of the leaf. Also recorded from young pods (Bland, 1997a).

Long corridor mine. As a rule the first part of the mine is lower-surface, the later part upper-surface. Often the loops are so dense that a secondary blotch is the result. Because upper- and lower-surface corridor segments often cross, the mine obtains a strange array of transparant patches. There is no association with the midrib. Frass in strings and thread fragments. Pupation outside the mine; exit slit in upper epidermis (Bladmineerders van Europa).

Mine not associated with the veins or midrib of the leaf (It is this character which enables distinction from another Agromyzid pest species - Liriomyza huidobriensis). The larvae may leave one leaf (if not large enough) and enter another leaf, via the petiole). It exits the leaf to pupate through a semi-circular slit in the upper surface of the leaf (British leafminers).

On 119 plant genera in 31 plant families of which only 4 plant genera in 2 plant families, but not yet on Armoracia, in Britain. On Armoracia elsewhere. Local, probably introduced to Britain. Widespread in continental Europe particularly in Botanical Gardens and glasshouses. Also recorded in Egypt.

Liriomyza bryoniae (Kaltenbach, 1858) [Diptera: Agromyzidae].

1d > Leaf-miner: Rather small, untidy, full depth, often branched corridor, often close to the leaf margin. Sides irregularly eaten out. Frass in a greyish-green central line that is interrupted from time to time, sometimes partly in strings. In times of rain the frass may run out and appear greenish. Usually several mines in a leaf (Bladmineerders van Europa). The body is whitish; head greyish brown with Y-shaped lighter marking. Pronotum with a pair of brownish shields. The mandibles have two teeth (Bladmineerders van Europa).

Mine of Ceutorhynchus contractus (as minutus) on Raphanus sativus Image: © WIllem Ellis (Bladmineerders en plantengallen van Europa)
Mine of Ceutorhynchus minutus on Raphanus sativus
Image: © Willem Ellis (Bladmineerders van Europa)
Ceutorhynchus minutus larva,  dorsal
Ceutorhynchus minutus larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)

Polyphagous. On numerous genera and species of Brassicaceae, Capparaceae, Resedaceae and Tropaeolaceae, including Cochlearia, but not yet on Armoracia, in Britain and numerous Brassicaceae, including Armoracia elsewhere. Widespread in Britain and continental Europe. Also recorded in the Republic of Ireland.

Ceutorhynchus minutus (Marsham, 1802) [Coleoptera: Curculionidae].



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