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

 

EUONYMUS. Spindle-tree. [Celastraceae]


Six species of Euonymus are recorded in Britain. These include the native Spindle-tree (E. europaeus).

Two British miners are recorded on Euonymus.

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

Spindle-tree - Euonymus europaeus
Spindle-tree
Euonymus europaeus


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


1a > Leaf-miner: A distinctive mine primarily above mid-rib, with irregular short lateral offshoots into leaf blade. Pupation external (Spencer, 1972: 51 (fig. 172), 55; Spencer, 1976: 270, 271 (fig. 486)).

Branched, whitish, upper-surface corridor; main axis overlying the midrib; side branches overlying the main lateral veins. (In Campanula and Phyteuma the mine is much less branched, sometimes nothing more than a corridor on top of the midrib). Frass in rather long strings. Usually the mines begins as a long and narrow, shallow, tortuous lower-surface corridor that ends upon the midrib but otherwise is not associated with the leaf venation. Often this initial corridor is filled with callus, and then even less conspicuous. Pupation outside the mine.

A linear mine on the upper surface, usually following the midrib and showing side branches along the veins. The frass is in strings.

Polyphagous. On more than 40 host genera in 15 families, but not yet on Euonymus, in Britain,. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Liriomyza strigata (Meigen, 1830) [Diptera: Agromyzidae].

1b > Leaf-miner: Larvae usually gregarious. Early mine an epidermal gallery leading to a contorted blotch with black frass. Subsequently two successive cones formed by folding the tip of a leaf downwards (British leafminers, as Caloptilia syringella). Often, many leaves on a single bush turn brown and curl up with the mines. The species can be a pest in gardens. The mine begins at a row of eggs along the midrib. The emerging larvae form relatively broad, inconspicuous, lower-surface corridor. Subsequently a large, grey brown or greenish brown, very opaque upper-surface blotch is made, occupied by ten or more larvae. The mine makes the leaf somewhat bumpy, but the leaf does not fold around the mine, like in Caloptilia cuculipennella. After some time the larvae leave the mine and continue feeding, still comunnally, in a downwards rolled leaf.

Gracillaria syringella larva
Gracillaria syringella larva
Image: © Willem Ellis (Bladmineerders van Europa)

On Symphoricarpos, Fraxinus, Jasminum, Ligustrum, Phillyrea and Syringa, but not yet on Euonymus, in Britain and Chionanthus, Euonymus (in key only), Forestiera, Forsythia, Fraxinus, Jasminum, Ligustrum, Phillyrea and Syringa elsewhere. Widespread in Britain, Ireland and continental Europe.

Gracillaria syringella (Fabricius, 1794) [Lepidoptera: Gracillariidae].



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