1a mine full depth; larva with chirinised head => 2

1b mine upper- or lower-surface; larva a maggot => 7

1c fleck mine; larva mines from a helicoidal case: Apterona helicinella

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

2a mine small, < 1 cm; larva, with abdominal feet, later lives free => 3

2b mine > 1 cm; larva, without abdominal feet, remains in the mine till pupation => 5

3a larva pale green; older larvae live at the underside of the leaf: Plutella xylostella

3b larva dark grey; older larvae live between spun leaves => 4

10a larva: pinacula colourless (the bases of the setae themselves are black) : Cnephasia incertana

4b pinacula black: Cnephasia asseclana

5a mine in the midrib or a thick vein, with short branches into the leaf blade: Ceutorhynchus pallidactylus

5b mine entirely in the leaf blade => 6

6a larva without feet; mine an untidy corridor: Ceutorhynchus minutus

6b larva with thoracic feet; mine a corridor the turns blotchy in the end: Phyllotreta nemorum

7a mine largely a broad corridor of slender blotch, positioned over the midrib => 8

7b mine nit associated with the midrib => 9

8a irregular blotch with few, short, side branches; frass in short strings: Liriomyza xanthocera

8b broad, pinnately branched corridor; side branches numerous, over the lateral veins; frass in longer strings: Liriomyza strigata

9a gallery from start to end => 10

9b narrow gallery, ending in a blotch => 11

10a frass in isolated grains; pupation within the mine, in a, generally lower-surface, pupal chamber: Chromatomyia horticola

10b frass in strings; pupation external: Liriomyza brassicae

11a frass in black thread fragments; mines in May-June: Liriomyza xanthocera

11b frass powdery, in blackish-green clouds; mines in May-October: Scaptomyza flava