1a mine full depth (except perhaps a green centre); larva with chitinised head => 2

1b mine upper- or lower-surface; larva a maggot => 6

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

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

2b mine > 1 cm; larve, never with prolegs, mines all its life => 4

3a mine contains frass; larva: pinacula white: Plutella xylostella

3b mine contains (almost) no frass; pinacula black: Cnephasia asseclana

4a blotch, with green centre; frass dispersed: Xenostrongylus lateralis

4b mine different => 5

5a frass partly in strings; larva without thoracic feet: Ceutorhynchus minutus

5b frass in lumps; mine an irregular blotch; larva with thoracic feet: Phyllotreta nemorum

6a frass in well-spaced grains: Chromatomyia horticola

6b frass in strings => 7

6c frass powdery, in blackish-green clouds (often visible only after the mine has been opened): Scaptomyza flava

7a broad coridor, overlying th midrib, with lateral extensions : Liriomyza xanthocera

7b corridor, not associated with the midrib, mostlly ending in a secondary blotch: Liriomyza bryoniae