Cirsium, spear thistle and relatives

fam. Asteraceae

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

1b mine not associated with the midrib => 7

1c galls, etc => 100

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

2b mine full depth; larva with chitinised head => 6

3a larva in the basis of the midrib, that is galled and swollen; from there short corridors enter the lamina: Phytomyza continua

3b midrib not galled or swollen; mine not in such a basal position => 4

4a side branches slender, not very numerous; frass in strings: Liriomyza strigata

4b side branches short, numerous; frass in grains => 5

5a mine begins at an egg shell; frass grains minute, forming a shadow line along the midrib and side veins: Pegomya terebrans

5b no visible egg shell; frass grains coarser, most of them on top of the midrib: Agromyza apfelbecki

6a larva without feet: Orthochaetes insignis

6b larva with thoracic and abdominal feet: Scrobipalpa acuminatella (but see also S. pauperella)

7a mine small and of indefinite shape, often in numbers on a leaf => 8

7b blotch mine => 12

7cmore or less broad gallery => 17

7d fleck mine => 29

7e “pseudo mine”: the larva causes window feeding, actually living free between the upper epidermis and the dense layer of felt at the underside of the leaf: Agonopterix ferocella

8a mines puckered by silk deposited interiorly; larvae, sombre coloured, with thoracic feet => 9

8b mines flat; larvae whitish, without feet => 11

9a larva: pinacula colourless (the bases of the setae themselves are black) : Cnephasia incertana

9b pinacula black => 10

10a larva: behind/below the anus a chitinous comb: Cnephasia asseclana

10b anal comb absent: Cnephasia stephensiana

11a the larva mines all its life: Phytosciara macrotricha

11b older larvae live free under the leaf, causing window feeding: Phytosciara halterata

12a larva a maggot => 13

12b larva with distinct head and thoracic legs => 14

13a mine very transparant; larva solitary: Pegomya steini

13b mine brownish black; larvae comunal: Phytomyza heterophylli

14a mine strongly puckered: Cnephasia lineata

14b mine almost flat => 15

15a mining larva: pinacula concolorous with (yellowish green): Agonopterix carduella

15b pinacula black => 16

16a larva: head light brown; mine contains much frass: Tebenna micalis

16b head black; mine with little or no frass: Agonopterix nanatella aridella

17a mine small; larva later lives free in a spinning under the leaf => 18

17b mine large; larva remains in the mine untill close to pupation => 20

18a head yellowish to brown; pale yellow or green: Agonopterix arenella

18b head black; green => 19

19a matt green; June – early July: Agonopterix subpropinquella

19b apple green; July – early August: Agonopterix propinquella

20a mine at least partly full depth; larva with feet and head => 21

20b mine upper- or lower-surface, or inter-parenchymal; larva a maggot => 23

21a mine usually with a central, thread-like frass line: Apteropeda orbiculata

21b frass in scattered grains => 22

22a larva hibernates in the mine; corridor follows the leaf margin: Sphaeroderma testaceum

22b larva leaves the mine prior to hibernation; corridor less strongly associated with the leaf margin: Sphaeroderma rubidum

23a pupation within the mine => 24

23b larva leaves the mine before pupation => 25

24a puparium metallic black: Phytomyza autumnalis

24b healthy puparia white (parasitised or dead puparia are brownish black!) => 25

25a mine very long, largely inter-parenchymal, yellow-green**; larva with a short frontal appendage: Phytomyza spinaciae

25b mine shorter, upper- or lower-surface, whitish**; larva without frontal appendage: Chromatomyia cf. syngenesiae

26a frass in discrete grains, their distance larger than their diameter; corridor loosely wound => 27

26b frass at least partly in strings or pearl chains; corridor closely wound, forming a secondary blotch => 28

27a frass grains small, not very widely apart; mine short, often in a single leaf segment: Phytomyza cirsii

27b frass grains large, wide apart; mine unusually long: Phytomyza albiceps

28a larva: rear spiraculum with 7-9 papillae; mine essentially upper-surface but with lower-surface parts, causing the secondary blotch to have semitransparant patches: Liriomyza bryoniae

28b larva: rear spiraculum with 3 papillae; mine fully upper-surface: Liriomyza soror

29a the larva lives free under a leaf, making a slit-like opening and eating away so much leaf tissue the the front half of its disappears in the leaf: Jordanita globulariae, J. graeca, J. notata, J. tenuicornis

29b the larva mines the lower leaves from a silken tube: Scrobipalpula psilella

29c the larva mines from a case => 30

30a case helicoidal: Apterona helicoidella

30b case more or less straight => 31

31a case dark brown: Coleophora paripennella

31b case straw coloured : Coleophora peribenanderi

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 anthocoptes; Epitrimerus cardui

103 – Coleoptera

103a Apionidae: Ceratapion onopordi

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

106 – Hymenoptera

106a Cynipidae: Isocolus cirsii

108 – smut fungi

108a Glomosporiaceae: Thecaphora trailii

108b Ustilaginaceae: Ustlago cardui

109 – powdery and downy mildews

109a Erysiphaceae: Erysiphe mayorii var. mayorii; Golovinomyces montagnei, Leveillula lappae; Podosphaera xanthii

109b Peronosporaceae: Bremia cirsii

110 – other causers

110a Fungi, Albuginaceae: Pustula obtusata, Pustula spinulosa

110b Fungi, Synchytriaceae: Synchytrium aureum, globosum, sanguineum

110c Lepidoptera, Tortricidae: Epiblema scutulana

** The leaves of Cirsium oleraceum are too thin for an inter-parenchymal mine; here the corridor is upper-surface and white, and only the larvae, and to a limited extent the length of the corridor, are diagnostic.

Not included in the key: Aulagromyza carlinae; Coleophora follicularis; Gnorimoschema ochraceellum (mystification); Liriomyza bryoniae, trifolii; Phytomyza cirsiophaga (insufficiently known).

29/05/2017