1a corridor, vanishing into the midrib => 2

1b corridor or blotch, not ending in the midrib => 3

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

2a larva a maggot: Phytomyza rufipes

2b larva with sclerotised head: Ceutorhynchus pallidactylus

3a mine full depth; larva with chitinised head => 4

3b mine upper- or lower-surface; larva a headless maggot => 6

4a tiny corridor or blotch, < 5 mm: Plutella xylostella

4b blotch, not preceded by a corridor, with a green centre: Xenostrongylus lateralis

4c corridor, > 10 mm => 5

5a larva without feet; mine an untidy corridor: Ceutorhynchus minutus

5b larva with thoracic feet; latest part of the mine blotchy: Phyllotreta nemorum

6a mine largely a broad corridor or elongated blotch, positioned over the midrib => 7

6b mine not associated with the midrib => 8

7a irregular blotch over the midrib, with few, short side branches without apparent direction; frass in short thread fragments: Liriomyza xanthocera

7b broad corridor over the midrib, its more numerous side branches positioned over the main lateral veins; frass in longer pearl chains: Liriomyza strigata

8a final part of the mine blotchy => 9

8b mine a corridor throughout => 10

9a frass in thread fragments; mines in May-June; larva: rear spiraculum with 3 clear papillae: Liriomyza xanthocera

9b frass in extremely fine grains, concentrated in greenish-black clouds; mines in May-October; rear spiraculum seemingly with 1 pointed papilla: Scaptomyza flava

10a puparium in the mine: Chromatomyia horticola

10b prior to pupation the larva leaves the mine through a semicircular exit slit: Liriomyza bryoniae