Knautia field scabious

Dichotomous table for leafminers

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

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

1c galls, etc => Tables for all parasites per species

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 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 lumps near the end 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

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, stephensiana; Trachys troglodytes subglaber.

mod 10.ix.2018