Castanea, sweet chestnut

fam. Fagaceae

1a mine with an excision, either throughout, or only of the upper epidermis => 2

1b blotch, with a quickly widening preceding corridor => 3

1c a narrow corridor from start to end => 8

1d a narrow corridor, eventually widened into a primary blotch => 13

1e tentiform mine: Phyllonorycter messaniella

1f fleck mine => 15

1g galls, etc => 100

2a excision throughout the leaf, about the size of the mine itself: Incurvaria masculella

2b excision of only the upper epidermis, much smaller than the mine: Tischeria decidua

3a mine transparant, frass in long threads: Dyseriocrania subpurpurella

3b mine opaque and/or frass in granules => 4

4a mine full depth, < 1 cm: Incurvaria masculella

4b mine upper-surface, > 1 cm => 5

5a larva makes in the mine a discoid cocoon in which it often rests, curved in u-shape => 6

5b larva does not make a cocon, never resting in that position: Profenusa pygmaea

6a mine milk-white, sometimes with orange tinges; no concentric lines: Tischeria ekebladella

6b mine much darker (brown, grey, brick-red); with concentric darker arcs (frass) around some point at the side of the mine => 7

7a mine brick-red with brown-black arc lines (rather common): Tischeria dodonaea

7b mine yellowish-brown with greyish-green arc lines (rare): Tischeria decidua

8a corridor < 1 cm, hook-shaped, usually against the midrib => 9

8b corridor much longer => 11

9a mining larva: head yellowish white (rarely on this hostplant): Bucculatrix thoracella

9b head light or dark brown => 10

10a pupa: abd. 2 dorsally with a transverse row of enlarged spines: Bucculatrix demaryella castaneae

10b such a transverse row of spines only on the more posterior segments: Bucculatrix ulmella

11a at the beginning of the egg a shining egg shell; mine clearly widening; larval chamber plump, < 3 times as long as wide => 12

11b no egg shell; corridor hardly widening; larval chamber slender, > 3 times as long as wide: Lyonetia clerkella

12a corridor filled over its whole width with coiled frass (green when fresh, later turning brown); larva green: Stigmella basiguttella

12b frass brown or black, not coiled, in a broad or narrow line, always leaving a transparant zone at the sides: Stigmella samiatella

13a the blotch has a cut at the leaf underside, through which most of the frass is expelled: Ectoedemia subbimaculella

13b no cut in the blotch => 14

14a corridor part of the mine runs in the direction of the midrib; larva with brown-black head; mostly in yellow, perhaps fallen, leaves in a green island: Ectoedemia heringi

14b corridor part runs parallel to, or away from, the midrib; larva with a pale brown head; usually in green leaves: Ectoedemia albifasciella

15a lobe case: Coleophora violacea

15b tubular leaf case: Coleophora lutipennella

15c pistol case: Coleophora anatipenella

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

104 – Diptera

104a Cecidomyiidae: Mikiola fagi

105 – Hemiptera

105a Aphididae: Lachnus longirostris, roboris

106 – Hymenoptera

106a Cynipidae: Dryocosmus kuriphilus

109 – powdery and downy mildews

109a Erysiphaceae: Erysiphe alphitoides; Phyllactinia roboris

110 – andere veroorzakers

110a Fungi, Microstromataceae: Microstroma album

110b Lepidoptera, Gracillariidae: Spulerina simploniella

110c Plantae, Loranthaceae: Loranthus europaeus

110d Plantae, Santalaceae: Viscum album

Not included in the key: Acrocercops brongniardella; Caloptilia alchimiella, robustella; Coleophora flavipennella; Povolnya leucapennella.