Barbarea, Yellow Rocket

fam. Brassicaceae

1a stem borer, rarely penetrating into petiole and midrib, with a isolated excursions into the leaf blade: Psylliodes napi

1b real leafminer => 2

1c galls, etc => 100

2a mine full depth; larva with chitinised head => 3

2b mine upper- or lower-surface (sometimes a few full depth patches); larva a maggot => 7

3a small blotch mine, < 1 cm; larva with toracal, and abdominal feet; elder larvae living free => 4

3b mine > 1cm, may be a corridor; larva remains in the mine till pupation => 6

4a larva: prothoracic plate largely blackisch brown; older larve live among spun leaveas => 5

4b prothoracic plate bone colourd, a few spots; older larvae live free under a leaf: Plutella xylostella

5a larva: pinacula colourless (though the bases of the setae themselves are black): Cnephasia incertana

5b pinacula black: Cnephasia stephensiana

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

6b larva with thoracic feet; mine eventually widening into a blotch: Phyllotreta nemorum

7a corridor from start to end => 8

7b irregular blotch => 11

8a pinnately branched broad corridor overlying the midrib: Liriomyza strigata

8b corridor little branched, not associated with the midrib => 9

8a puparium in the mine in a, usually lower-surface, pupal chamber; frass in discrete grains: Chromatomyia horticola

8b larva leaves the mine before pupation, through a semicircular exit slit; frass in thread fragments => 10

10a mine usually forms a secondary blotch: Liriomyza bryoniae

10b usually no secondary blotch: Liriomyza brassicae

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

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

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 Heteroderidae: Heterodera schachtii

102 – Acari

102a Eriophyidae: Aceria drabae

103 – Coleoptera

103a Curculionidae: Aulacobaris coerulescens, lepidii; Ceutorhynchus assimilis, chalibaeus

104 – Diptera

104a Cecidomyiidae: Contarinia nasturtii; Dasineura sisymbrii, stelteri

105 – Hemiptera

105a Aphididae: Lipaphis pseudobrassicae; Pseudobrevicoryne buhri

107 – rust fungi

107a Pucciniaceae: Puccinia isiacae

109 – powdery and downy mildews

109a Erysiphaceae: Erysiphe cruciferarum

109b Peronosporaceae: Hyaloperonospora barbareae

110 – other causers

110a Fungi, Albuginaceae: Albugo candida

110b Plasmodiophoromycota, Plasmodiophoraceae: Plasmodiophora brassicae

Not included in the key: Ceutorhynchus napi.