Betula, birch

fam. Betulaceae

1a mine ends in a round or oval excision => 2

1b blotch without a preceding corridor (or this corridor < 3 mm) => 6

1c blotch preceded by a corridor => 23

1d corridor from start to end => 30

1e short corridor that widens so fast and strongly that it could as well be called a triangular blotch; elliptic larva always present: Rhamphus pulicarius

1f tentiform mine => 41

1g fleck mine => 49

1h galls, etc => 100

2a excision initially a blotch, without preceding corridor, or corridor < 5 mm => 3

2b excision preceded by a narrow or wide corridor >> 5 mm (may be inside a vein) => 4

3a excision elliptic, ca. 3 x 5 mm: first stage mines of Coleophora-species

3b excision circular, ca. 5 mm in diameter, often several in a leaf: Incurvaria pectinea

4a main part of the mine within the midrib and/or a thick vein; from there a short yellow-green corridor enters the leaf disk, followed by an oval excision: Heliozela hammoniella

4b mine not associated with midrib of thick veins => 5

5a corridor gradually widening, excision almost circular: Orchestes rusci

5b corridor very long, thread-thin, suddenly widening into an oval excision: Phylloporia bistrigella

6a at the start of the mine, on the leaf margin, a shining black drop of dried secretion: Trachys minutus

6b no such drom => 7

7a frass in threads of one or more cm long => 8

7b frass in grains, sometimes short thread fragments => 12

8a mine in the centre of the leaf => 25

8b mine at the leaf margin => 9

9a larvae usually communal; very transparant, almost hyaline: Eriocrania cicatricella

9b larva solitary; grey or white => 10

10a full grown larva slate grey; vacated mines still recognisable by the presence of a gray larval skin: Eriocrania sangii

10b larva milk white at all stages => 11

11a rear corners of the head capsule elongate and strongly sclerotised, black; because the head is retracted witihin the prothorax it appears as two vague black spots: Heringocrania unimaculella

11b prothorax without “black spots”: Eriocrania semipurpurella

12a blotch round, with a dark centre => 13

12b blotch round or not, never with a dark centre => 14

13a frass in clear arcs around the dark centre: Leucoptera malifoliella

13b outside the centre only little frass, not in arcs: Ectoedemia occultella

14a mine full depth, ≤ 2 mm, with a few grains of frass, with a hole through which the mine has been vacated: Swammerdamia caesiella

14b mine not like this => 15

15a larva squat, without feet (larva of Curculionidae) => 16

15b larva slender, with thoracic feet => 17

16a blotch comma- or pear-shaped, often several in a leaf; mine contains much frass, making it dark and inconspicuous; no cocoon: Rhamphus pulicarius

16b mine larger, more transparant, solitary; larva eventually makes a globular cocoon in the mine: Orchestes jota

17a larva bright pink, marbled; under the leaf a loose spinning is present, in which grains of ejected frass are caught: Atemelia torquatella

17b larva pale yellow (except for some eventual dark brown spots); sawfly larva => 18

18a mine begins in the centre of the leaf => 19

18b mine begins at the margin => 20

(The oldest part of the mine usually is less deep, therefore greener in transparancy, than later parts. The frass here in smaller grains. Often an oviposition scar is recognisable as a bright green flat wart at the leaf upper surface.)

19a larva: thoracic feet well developed; usally sveral mines, of different sizes, in a leaf: Fenusa pumila

19b thoracic feet reduced to stumps; mine usually solitary: Profenusa thomsoni

20a mine begins with a triangular section (one angle at the very leaf margin), crammed with frass; from there an, often quite large, blotch develops: Fenusella nana

20b mine a broad blotch from the beginning, without such an initial accumulation of frass => 21

21a oldest part of the mine, near the leaf margin, dark reddish brown; mine contains little frass; larva eventually makes a flat circular cocoon: Heterarthrus nemoratus

21b mine pale brown throughout, containing much frass; never a cocoon => 22

22a larvae leave the mine in June: Scolioneura vicina

22b larvae in the mine from August till October: Scolioneura betuleti

23a frass in long threads => 24

23b frass in grains or flakes => 25

24a initial corridor gradually widening into a blotch; larvae in mid May: Eriocrania salopiella

24b initial corridor suddenly, often under an angle, widening into a blotch; larvae in mid June: Eriocrania sparrmannella

25a mine begin in or on the midrib => 26

25b mine begins elsewhere => 27

26a oviposition, at the lower side of the midrib, leaves a big, deep, scar; from there a corridor starts that widens strongly close to the leaf tip; apical part of the leaf often crumpled: Orchestes testaceus

26b no strong scar; leaf tip never crumpled: Tachyerges pseudostigma & T. stigma

27a mine starts at an ( lower-surface, globular, shining) egg shell; from there a strongly tortuous gallery, that widens into a blotch: Ectoedemia minimella

27b no egg shell visible; initial corridor not strongly contorted => 28

28a initial corridor long and very slender: Lyonetia prunifoliella

28b initial corridor broad and short, often overrun by the later blotch => 29

29a larva slender with (short) thoracic feet; leaves the mine prior to pupation: Profenusa thomsoni

29b larva squat, without feet; pupates in the mine in a globular cocoon: Orchestes jota

30a small corridor, often branched, without frass: Recurvaria nanella

30b mine unbranched, containing frass => 31

31a mine shorter than 1 cm: Bucculatrix demaryella, in Central Europe also Bucculatrix thoracella

31b mine much longer => 32

32a mine upper-surface, greenish: Agromyza alnibetulae

32b mine full depth, whitish => 33

33a mine begins at an egg shell, that is globular and shining, and may be upper- or lower-surface; mine never starts in the midrib (Stigmella-species) => 34

33b no egg shell at the beginning of the corridor => 40

34a in most of the length of the corridor the frass is coiled => 35

34b frass nowhere coiled => 36

35a frass (in fresh mines) green, the coils filling the width of the corridor; initial part of the corridor contorted, making the leaf tissue turn brown: Stigmella continuella

35b frass black, even in fresh mines, never filling the width of the corridor; mine usually starting near the leaf margin; initial stretch not strongly contorted, not discolouring the leaf tissue: Stigmella sakhalinella

36a corridor long and angular; frass line in the second half of the mine very narrow => 37

36b corridor shorter, more tortuous; frass line in the second half wider, often interrupted => 38

37a first part of the corridor completely filled with green (turning brown) frass: Stigmella lapponica

37b also in the first part of the corridor the frass in a narrow median line: Stigmella confusella, and, thermophilic species from Central Europe, Stigmella naturnella

38a mine in Lapland, on Betula nana: Stigmella tristis

38b mine in more temperate regions, also on other Birch species => 39

39a initial part of the corridor lower-surface, green in transparancy; usually 1 mine per leaf; August-November: Stigmella luteella**

39b corridor full depth from the start on, transparant; often > 1 mines per leaf; June-October: Stigmella betulicola**

40a oviposition in the midrib (usually in its apical part) causing it to gall and swell; early spring: Anoplus plantaris

40b oviposition never in the midrib; mines throughout the summer: Lyonetia clerkella

41a mine upper-surface => 42

41b mine lower-surface => 44

42a mine silvery; pupation in the mine: Phyllonorycter corylifoliella

42b mine brownish; larva leaves the mine early and continues living in a rolled part of the leaf; several rolls are made and eaten out => 43

43a final leaf roll lengthwise: Caloptilia populetorum (+ probably C. suberinella)

43b final leaf rol transverse: Caloptilia betulicola

44a mined cuticula brownish; larva leaves the mine early and continues living in a folded or rolled part of the leaf; several rolls are made and eaten out => 45

44b mined cuticula (pale) green; pupation in the mine => 47

45a free living larva in a folded leaf margin => 46

45b free living larva in a rolled leaf => 43

45c free living larva in a leaf that has been folded up downwards; only on Betula nana: Parornix polygrammella

46a mine randomly positioned, preceded by a short corridor: Parornix betulae and, in northern Europe, Parornix loganella

46b mine at the leaf margin, preceded by a long corridor that often follows the midrib for some distance, before turning towards the leaf margin (rare on Birch): Caloptilia stigmatella

47a mine 15-20 mm; lower epidermis with 7-12 folds: Phyllonorycter cavella

47b mine 10-15 mm; lower epidermis with 1-6 folds => 48

48a pupa not in a cocoon; almost exclusively on seedlings: Phyllonorycter anderidae

48b pupa in a coccon (may consist of no more than a loose spinning); not restricted to seedlings: Phyllonorycter ulmifoliella

49a case helicoidal: Apterona helicoidella

49b case tubular => 50

50a lobe case => 51

50b composite leaf case => 54

50c tubular leaf case => 56

50d spatulate leaf case => 57

50e pistol case, with a pallium => 58

51a case plump, rear end strongly curved downwards => 52

51b case slender, rear end almost straight => 53

52a case funnel-shaped; rear end strongly narrowed: Coleophora cornutella

52b case pistol-shaped, rear end not strongly narrowed: Coleophora fuscocuprella

53a case brownish black; mouth angle 0°: Coleophora violacea

53b case whitish; mouth angle 10°-30°: Coleophora potentillae

54a extensions of the case made out of bits of epidermis => 55

54b extension made out of narrow rings; case strongly curved; September-May: Coleophora serratella (juvenile case)

55a connection between the consecutive parts of the case “seamless”; in spring and early summer case unicolorous; August-October: Coleophora orbitella

55b connection between the parts untidy, frayed; in spring and early summer these parts with diffferent colours; August-June: Coleophora binderella

56a case flattened tubular, with a narrow dorsal keel, smooth, April-June: Coleophora serratella (final case)

56b case zeppelin-shaped with intidy leaf fragments attached to it, August-July: Coleophora siccifolia

57a full grown case 8-11 mm; mouth angle 45°: Coleophora milvipennis

57b case 13 mm; mouth angle 15° (occurence on Birch, at least in western Europe, dubious): Coleophora alnifoliae

58a mouth angle 70-80°; case somewhat shiny; : Coleophora anatipenella

58b mouth angle 30-45°; case mostly rough and dull: Coleophora betulella

100a Nematoda => 101

100b Acari => 102

100c Coleoptera => 103

100e Diptera => 104

100f Hemiptera => 105

100d Hymenoptera => 106

100g rust fungi => 107

100h smut fungi => 108

100i powdery and downy mildews => 109

100j other causers => 110

103 – Coleoptera

103a Apionidae: Betulapion simile

103b Curculionidae: Cryptorhynchus lapathi

107 – rust fungi

107a Pucciniastraceae: Melampsoridium betulinum

109 – powdery and downy mildews

109a Erysiphaceae: Erysiphe ornata; Phyllactinia betulae; Podosphaera erineophila

110 – other causers

110a Bacteria, Rhizobiaceae: Agrobacterium tumefaciens

110b Fungi, Synchytriaceae: Synchytrium aureum

110c Fungi, Taphrinaceae: Taphrina bacteriosperma, betulae, betulina, carnea, nana

110d Fungi, Venturiales: Fusicladium scribnerianum

110e Lepidoptera, Incurvariidae: Lampronia fuscatella

110f Lepidopoptera, Tortricidae: ? Acleris notana; Cochylis nana; Epinotia bilunana, immundana

110h Lepidoptera, Yponomeutidae: Argyresthia brockeella, goedartella

110h Plantae, Santalaceae: Viscum album

** A mine of St. glutinosae has recently been found by van Nieukerken on birch.

Not included in the key: Coleophora currucipennella, prunifoliae, vacciniella; Ectoedemia subbimaculella; Parornix traugotti; Roeslerstammia erxlebella; Stigmella alnetella; Swammerdamia passerella.

09/10/2016