Plant Parasites of Europe

leafminers, galls and fungi


Corylus hazel

(For a dichotomous table for galls on Corylus by Hans Roskam click here)

Dichotomous table for leafminers

1a corridor => 2

1b blotch, in which eventually an excision is made that is hardly smaller than the blotch itself => 5

1c blotch without an excision, preceded by a corridor => 7

1d blotch without an excision, not preceded by a corridor => 8

1e tentiform mine => 12

1f fleck mine => 13

1g galls, etc => Tables for all parasites per species

2a corridor branched, without frass (rare on this hostplant): Recurvaria nanella

2b corridor containing much frass, not or hardly branched => 3

3a corridor < 1 cm; larval chamber > 3 x as long as wide (rare on this host plant): Bucculatrix demaryella

3b corridor > 1 cm; larval chamber proportionally shorter => 4

4a gallery quite narrow over its entire length (just as wide as the larva itself); frass in a sharp narrow central line, in the first half of the mine rarely, in the second half often wider; mine long and usually angular, often following a vein over large stretches. Egg at the lower surface, against a vein, not in a vein axill. Larva tight in the mine, venter upwards, head light brown. Exit slit usually at underside, rarely upper side: Stigmella microtheriella

4b gallery wider, especially in second half much wide than the larva; frass line variable, cloudy, at start often green, sometimes rather narrow, generally wide; mine not angular, not following a vein. Egg invariably in or very close to a vein axill, at leaf underside. Larve venter downwards, head darkly spotted. Exit slit invariably at upper side: Stigmella floslactella

5a larva without feet (occurrence on this host plant dubious): Orchestes avellanae

5b larva with thoracic feet => 6

6a larva**: pronotum brown, meso- and metanotum each with a pair of dark spots: Incurvaria masculella

6b larva**: entire thorax dorsally yellowish-grey: Incurvaria pectinea

7a initial corridor strongly wound; does not begin on the midrib or petiole: Ectoedemia minimella

7b intitial corridor not contorted, starting on petiole or midrib, widening into a large blotch in the basal part of the leaf: Tachyerges pseudostigma & T. stigma

8a on the oviposition site (almost always the leaf tip) a shining black drop of dried secretion: Trachys minutus

8b no such drop => 9

9a mines begins at the margin of the leaf; frass often in long threads; larva without feet => 10

9b mine does not begin at the leaf margin; frass in loose granules; larva with feet => 11

10a larva: prothorax entirely white (occurrence on this host plant uncertain): Dyseriocrania subpurpurella

10b larva: pronotum with two irregular black spots: Paracrania chrysolepidella

11a silvery roundish upper-surface blotch: Phyllonorycter coryli (young mine)

11b small angular transparant mine between two veins or in an axil; frass in a corner; larva later lives free in a folded leaf margin: Parornix devoniella

12a upper-surface tentiform mine; initially flat, silvery: Phyllonorycter coryli

12b lower-surface tentiform mine: Phyllonorycter nicellii

13a pistol case => 14

13b lobe case => 15

13c composite leaf case => 16

13d tubular leaf case: Coleophora serratella

13e spatelvormige bladzak => 18

14a pallium with ear-like appendages: Coleophora currucipennella

14b pallium witohut such decorations: Coleophora anatipenella

15a rear end of the case strongly bent; mouth angle 60-80°: Coleophora fuscocuprella

15b case straight; mouth angle 0°: Coleophora violacea

16a extension of the case by addition of small rings to the mouth margin; case strongly curved: Coleophora serratella (youth case)

16b extension of the case by means of pieces of plant cuticula => 17

17a old and new parts of the mine have the same colour; cases in August-October: Coleophora orbitella

17b old and new parts of the mine differ in colour; cases in September-May: Coleophora binderella

18a mouth angle 0-10°, case lies flat on the leaf: Coleophora badiipennella

18b mouth angle c. 45°, case stands obliquely on the leaf: Coleophora milvipennis

** This applies to the older larvae, after they have dropped themselves on the ground; it is still unclear how they compare to the mining larvae.

Not included in the key: Caenorhinus mannerheimii; Coleophora ahenella; Lampronia intermediella.

Tables for all parasites per species

Last modified 13.ii.2021