Sorbus mountain ash
Incl. Aucuparia.
(For a dichotomous table for galls on Sorbus by Hans Roskam click here)
Dichotomous table for leafminers
1a small blotch mine, with an excision, not much smaller then the blotch itself: Incurvaria pectinea
1b primary blotch, without an excision => 2
1c tentiform mine => 8
1d corridor, abruptly widening into a blotch: Stigmella sorbi
1e corridor from start to end, only weakly widening; there may be a secondary blotch => 15
1f fleck mine => 21
1g galls, etc => Tables for all parasites per species
Dichotomous table for leafminers
1a small blotch mine, with an excision, not much smaller then the blotch itself: Incurvaria pectinea
1b primary blotch, without an excision => 2
1c tentiform mine => 8
1d corridor, abruptly widening into a blotch: Stigmella sorbi
1e corridor from start to end, only weakly widening; there may be a secondary blotch => 15
1f fleck mine => 21
1g galls, etc => Tables for all parasites per species
2a blotch full depth => 3
2b blotch upper- or lower-surface => 4
3a mine in spring: Incurvaria pectinea (young mine)
3b mine in autumn: Paraswammerdamia nebulella
4a oviposition spot (generally the tip of a leaflet) covered by a shining black drop of hardened secretion: Trachys minutus
4b no such drop => 5
5a blotch lower-surface, grey-brown: Parornix scoticella (young mine)
5b blotch upper-surface => 6
6a mine silvery, positioned over the midrib: Phyllonorycter corylifoliella or Ph. leucographella (young mines)
6b mine not silvery, not positioned over the midrib => 7
7a mine small, pear-shaped, often in number; much frass in a compact plug: Ramphus oxyacanthae
7b mine larger, circular; frass in concentric circles: Leucoptera malifoliella
8a mine upper-surface => 9
8b mine lower-surface => 10
9a full-grown mines silvery-white, without black speckles: Phyllonorycter leucographella
9b full-grown mines dirty grey because of numerous black speckles: Phyllonorycter corylifoliella
10a fresh mine grey-brown, larvae later live free => 11
10b fresh mine yellow green to whitish; pupation in the mine => 12
11a older larvae live in a leaf segment, rolled into a cone: Parornix anglicella
11b older larvae under a down-folded leaf margin or in a silk-covered leaf fold: Parornix scoticella
12a mine with some sharp folds; common species: Phyllonorycter sorbi
12b mine with either 1 strong or many feeble folds; rare species, in any case on this host plant => 13
13a pupa free in the mine, without a cocoon; cremaster with 1 pair of very slender spines: Phyllonorycter lantanella
13b pupa in a cocoon; cremaster with 2 pairs of short spines => 14
14a mine with numerous weak folds; frass in a line behind the cocoon: Phyllonorycter mespilella
14b mine with 1 sharp fold; frass in a clump in a corner of the mine: Phyllonorycter cydoniella
15a small branched mine without frass (rare on this host plant): Recurvaria nanella
15b mine does contain frass, not branched => 16
16a mine < 1 cm; first part stuffed with frass: Bucculatrix bechsteinella
16b mine much longer, not so full of frass => 17
17a no egg shell at the beginning of the corridor; corridor not infrequently crossing itself or the midrib; larval chamber at least 3 times as long as wide: Lyonetia clerkella
17b corridor begins at an egg shell, rarely crossing itself or the midrib; larval chamber less than 2 times as long as wide => 18
18a narrow corridor, crammed in a small space; frass in a narrow central line: Stigmella magdalenae
18b corridor winds freely through the leaf; frass coiled => 19
19a larva in June-July: Stigmella nylandriella
19b larva in September-November => 20
20a larva: meso- and metanotum with 10 setae: Stigmella nylandriella
20b meso- and metanotum with 9 setae (rare on Sorbus): Stigmella oxyacanthella
21a pistol case: Coleophora anatipenella
21b lobe case: Coleophora violacea
21c tubular silken case: Coleophora trigeminella
21d composite leaf case => 22
21e tubular leaf case => 23
22a rear end of the case crooked like the handle of a walking stick: Coleophora hemerobiella
21b rear end at most at right angle with the case: Coleophora spinella
23a case with large flaps attached to it: Coleophora siccifolia
23b case without such appendages => 24
24a case 8-11 mm, mouth angle 90°: Coleophora hemerobiella
24b case 6-7 mm, mouth angle 60°: Coleophora spinella
Not included in the key: Bucculatrix thoracella; Callisto pfaffenzelleri; Coleophora coracipennella, currucipennella, kroneella, prunifoliae, serratella; Ectoedemia atricollis; Lyonetia prunifoliella; Parornix anguliferella; Phyllonorycter blancardella, deschkai, hostis, oxyacanthae, cerisolella; Stigmella hahniella, hybnerella, mespilicola, torminalis.