Knautia, field scabious

fam. Caprifoliaceae

1a full depth corridor or blotch; larva with chitinised head => 2

1b mine upper- or lower-surface, greenish in transparancy; larva a maggot => 5

1c galls, etc => 100

2a larva with prolegs and pinacula; grey; older larvae live free among spun leaves => 3

2b larva without prolegs or pinacula; yellow of green; the larva mines all its life => 4

3a larva: pinacula colourless (the bases of the setae themselves are black) : Cnephasia incertana

3b pinacula black: Cnephasia stephensiana

4a large transparant blotch; at the oviposition site a small shiny black drop of dried secretion: Trachys troglodytes (and ? T. subglaber)

4b corridor; no shiny black drop: cf. Apteropeda orbiculata

5a primary blotch at the leaf margin; feeding lines very conspicuous: Agromyza woerzi

5b corridor or secondary blotch; no feeding lines visible => 6

6a corridors radiation from the midrib, or pinnately branched and positioned over the midrib => 7

6b no association with the midrib => 9

7a corridors all arising from the basal part of the midrib: Chromatomyia ramosa

7b corridor pinnately branched and positioned over the midrib => 8

8a puparium in the mine: Chromatomyia scabiosarum

8b puparium outside the mine: Liriomyza strigata

9a frass almost absent, or a few large lumops near the endi of the mine: Aulagromyza similis

9b frass in scattered grains => 10

10a leaf tissue around the mine intensively coloured violet; mine usually in the leaf tip: Chromatomyia succisae

10b leaf tissue not discoloured; no preferred position: Chromatomyia horticola

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 squalida

104 – Diptera

104a Cecidomyiidae: Contarinia dipsacearum

105 – Hemiptera

105a Aphididae: Aphis confusa

105b Triozidae: Trioza munda

107 – rust fungi

107a Pucciniacee: Aecidium succisae

108 – smut fungi

108a Microbotryaceae: Microbotryum flosculorum, scabiosae

109 – powdery and downy mildews

109a Erysiphaceae: Erysiphe knautiae; Podosphaera dipsacacearum

109b Peronosporaceae: Peronospora knautiae, violacea

110 – other causers

110a Fungi, Synchytriaceae: Synchytrium succisae

Palm (1989a) mentions field scabious as a host plant of Agonopterix arenella. Because all other known hosts of this species are Asteraceae this observation probably is incidental.

Not included in the key: Cnephasia incertana, stephensisiana; Trachys troglodytes subglaber.

18/11/2016