Brassica cabbage, turnip, mustard
(For a dichotomous table for galls on Brassica by Hans Roskam click here)
Dichotomous table for leafminers
1a mine begins or ends in the stem, petiole or midrib => 2
1b mine at most on the midrib, otherwise free in the leaf => 8
1c galls, etc => Tables for all parasites per species
Dichotomous table for leafminers
1a mine begins or ends in the stem, petiole or midrib => 2
1b mine at most on the midrib, otherwise free in the leaf => 8
1c galls, etc => Tables for all parasites per species
2a larva a maggot => 3
2b larva with chitinised head => 5
3a a corridor that ends upon a thick vein: Phytomyza rufipes
3b a corridor that begins on the midrib: Delia platura & D. florilega
3c narrow corridor, usually upper-surface, may be overrun later, that widens into an irregular blotch over, and partly within, the midrib => 4
4a frass in thread fragments; mine in May-June: Liriomyza xanthocera
4b frass powdery, in blackish-green clouds; mine in May-October: Scaptomyza flava
5a larva with thoracic feet; in autumn: Psylliodes napi
5b larva without thoracic feet; in spring => 6
6a mine begins in a part of the stem that is galled and swollen => 7
6b stem not swollen: Ceutorhynchus pallidactylus
7a swelling strong, containing ≥ 3 larvae: Ceutorhynchus napi
7b swelling weak, usually 1 larva: Ceutorhynchus rapae
8a mine full depth; larva with chitinised head => 9
8b mine upper- or lower-surface (some full depth patches may be present); larva a maggot => 14
9a small blotch, < 1 cm; older larve live free => 10
9b mine > 1 cm, corridor or blotch => 13
10a mine not contracted; older larvae live free at the underside of the leaf: Plutella xylostella
10b mine lightly contracted; older larvae among spun leaves => 11
11a larva: pinacula colourless (the bases of the setae themselves are black) : Cnephasia incertana
11b pinacula black => 12
12a larva: behind/below the anus a chitinous comb: Cnephasia asseclana
12b anal comb absent: Cnephasia stephensiana
13a larva without feet; mine an untidy corridor: Ceutorhynchus minutus
13b larva with thoracic feet; a corridor that widens in the end into a blotch: Phyllotreta nemorum
14a corridor from start to end => 15
14b irregular blotch, preceded by a corridor (that may be overrun) => 4
15a broad, pinnately branched corridor, its main branch overlying the midrib: Liriomyza strigata
15b corridor little branched, not pinnate, not associated with the midrib => 16
16a puparium in the mine in a, usually lower-surface, pupal chamber; frass in discrete grains: Chromatomyia horticola
16b before pupation the mine is vacated through a semicircular exit slit => 17
17a first part of the corridor in dense loops, suggesting a secondary blotch: Aulagromyza mamonowi
17b first part of the corridor more or less straight: Liriomyza brassicae
Not included in the key: Ceutorhynchus sulcicollis; Liriomyza trifolii; Scaptomyza griseola; Selania leplastriana; Xenostrongylus lateralis.