Carduus *, thistle

fam. Asteraceae

1a mine on or (partly) within the midrib => 2

1b mine not associated with the midrib => 6

1c galls, etc => 100

2a mine upper- or lower-surface; larva a maggot => 3

2b mine full depth; larva with recognisable head => 5

3a larva in the base of the swollen, galled midrib, with short extensions in the leaf: Phytomyza continua

3b midrib not galled, mine not situated so basally => 4

4a side branches slender, not very numerous; frass in strings; larva: cephalic skeleton with two backwards pointing arms: Liriomyza strigata

4b side branches short, numerous; frass in grains (most of it is invisible, deposited in the main branch); cephalic skeleton with three backwards pointing arms: Agromyza apfelbecki

5a larva without feet: Orthochaetes insignis

5b larva with prolegs and thoracic feet: Scrobipalpa acuminatella

6a mine small, of indefinite shape, sometimes many on a leaf; larva with well recognisable head => 7

6b mine not unusually small; corridor, blotch, or fleck; larva with or without a recgnisable head => 10

7a larva without feet => 8

7b larva with prolegs and thoracic feet => 9

8a the larva mines lifelong: Phytosciara macrotricha

8b older larva lives free under the leaf, causing window feeding: Phytosciara halterata

9a larva: pinacula colourless: Cnephasia incertana

9b pinacula black: Cnephasia stephensiana

10a fleck mine: larva mines from a case => 11

10b corridor or blotch; larva mines from the inside => 14

11a larva in a helicoidal case: Apterona helicoidella

11b larva in a more or less straight case => 12

12a case brownish black, lying almost flat on the leaf: Coleophora paripennella

12b case straw-coloured, not lying flat on the leaf => 13

13a mounth angle c. 50°, case c. 12 mm long: Coleophora peribenanderi

13b mounth angle 10-30°, case c. 10 mm (occurence on this hostplant uncertain): Coleophora follicularis

14a clear blotch => 15

14b corridor => 18

15a larva a maggot; near the start of the mine often an elliptic egg shell => 16

15b larva with feet and a chitinised head; no egg shell => 17

16a start of the mine (recognisable by an accumulation of frass) at the leaf margin; alpine species: Pegomya hessei

16b mines starts in tjhe centre of the leaf; lowland species: Pegomya steini

17a mine contains almost no frass: Agonopterix carduella

17b mine contains clear amounts of frass: Tebenna micalis

18a mine full depth; larva with feet and distinct head => 19

18b mine upper- or lower-surface, or inter-parenchymal; larva a maggot => 24

19a mine short; larva soon leaves and continues living free => 20

19b mine long; larva remains in the mine untill short before pupation => 22

20a head yellowish to brown; pale yellow or green: Agonopterix arenella

20b head black; green => 21

21a matt green; June – early July: Agonopterix subpropinquella

21b apple green; July – early August: Agonopterix propinquella

22a mine usually with a central, threadlike frass line: Apteropeda orbiculata

22b frass in grains, dispersed => 23

23a larva hibernates in the mine; corridor follows the leaf margin: Sphaeroderma testaceum

23b larva leaves the mine prior to hibernation; corridor less strongly associated with the leaf margin: Sphaeroderma rubidum

24a pupation in the mine => 25

24b larva leaves the mine prior to pupation => 26

25a mine long, largely inter-parenchymal, yellow-green: Phytomyza spinaciae

25b mine shorter, whitish: Chromatomyia cf. syngenesiae

26a frass in discrete grains (their distance larger than their diameter); no secondary blotch: Phytomyza cirsii

26b frass at least partly in strings; part of the corridor forms a secondary blotch: Liriomyza bryoniae

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

101 – Nematoda

101a Anguinidae: Ditylenchus dipsaci

102 – Acari

102a Eriophyidae: Aceria balasi; Epitrimerus cardui

103 – Coleoptera

103a Apionidae: Ceratapion onopordi

103b Curculionidae: Cleonis pigra; Larinus planus; Rhinocyllus conicus

105 – Hemiptera

105a Aphididae: Aphis wartenbergi

108 – smut fungi

108a Ustilaginaceae: Microbotryum cardui

109 – powdery and downy mildews

109a Erysiphaceae: Golovinomyces montagnei; Leveillula lappae

109b Peronosporaceae: Bremia lactucae

110 – other causers

110a Lepidoptera, Tortricidae: Epiblema scutulana

Not included in the key: Coleophora trochilella; Jordanita notata; Pegomya terebrans; Phytomyza cirsiophaga (insufficiently known).; Scrobipalpa perinii.

See also Alfredia

01/11/2016