Capsella, shepherd’s purse

fam. Brassicaceae

1a corridors, radiating from the leaf base or the midrib => 2

1b mine different => 4

1c galls, etc => 100

2a the mine begins at a gall in the petiole: Ceutorhynchus chalibaeus

2b no gall in the petiole => 3

3a side branches originate from the midrib: Ceutorhynchus erysimi

3b side branches originate from a main branch that lies on top of the midrib: Liriomyza strigata

4a larva with recognisable head => 5

4b larva a maggot => 8

5a larva with thoracic feet => 6

5b larva witout feet: Ceutorhynchus minutus

6a larva with prolegs => 7

6b no prolegs: Phyllotreta nemorum

7a older larvae live free under the leaf, causing window feeding: Plutella xylostella

7b older larvae live among spun leaves: Cnephasia incertana

8a frass powdery, in dark green clouds in remote corners of the mine: Scaptomyza flava

8b frass in black grains or strings => 9

9a pupation within the mine, in a, usually lower-surface, pupal chamber: Chromatomyia horticola

9b pupation external => 10

10a corridor from start to end (although here and there branches may coalesce into a secondary blotch): Liriomyza bryoniae

10b mine begins as a corridor but widens, usually on top of the midrib, into an irregular primary blotch: Liriomyza xanthocera

100a Nematoda => 101

100b Acari => 102

100c Coleoptera => 103

100e Diptera => 104

100f Hemiptera => 105

100d Hymenoptera => 106

100g rust fungi => 107

100h smut fungi => 108

100i powdery and downy mildews => 109

100j other causers => 110

101 – Nematoda

101a Anguinidae: Ditylenchus dipsaci

101b Heeroderidae: Heterodera cruciferae, schachtii

102 – Acari

102a Eriophyidae: Aceria drabae

103 – Coleoptera

103a Curculionidae: Ceutorhynchus assimilis, chalibaeus

104 – Diptera

104a Cecidomyiidae: Dasineura napi; Gephyraulus capsellae

105 – Hemiptera

105a Aphididae: Brevicoryne brassicae; Lipaphis erysimi, pseudobrassicae

105b Asterolecaniidae: Planchonia arabidis

107 – rust fungi

107a Pucciniaceae: Puccinia isiacae

109 – powdery and downy mildews

109a Erysiphaceae: Erysiphe cruciferarum; Golovinomyces orontii; Podosphaera drabae

109b Peronosporaceae: Hyaloperonospora parasitica

110 – other causers

110a Fungi, Albuginaceae: Albugo candida

110b Fungi, Plasmodiophoraceae: Plasmodiophora brassicae

110c Fungi, Synchytriaceae: Synchytrium aureum

Not included in the key: Liriomyza trifolii.