Armoracia, horse-radish

fam. Brassicaceae

1a mine full depth; larva with chitinised head => 2

1b mine upper- or lower-surface; larva a maggot => 5

1c galls, etc => 100

2a larva primarily a borer in the petiole, sometimes making an excursion into the leaf blade: Phyllotreta armoraciae

2b mine entirely within the leaf => 3

3a mine small, < 1 cm; frass in discrete grains; larva with abdominal and thoracic feet, lives later free: Plutella xylostella

3b mine > 1 cm, frass different; larva without abdominal feet => 4

4a frass partly in strings; mine irregular, corridor-like; larva without thoracic feet: Ceutorhynchus minutus

4b frass in lumps; mine an irregular blotch; larva with thoracic feet: Phyllotreta nemorum

5a narrow corridor, generally lower-surface, that seems to end upon a thick vein: Phytomyza rufipes

5b corridor does not end upon a vein => 6

6a frass powdery, in blackish-green clouds, often only visible after opening the mine: Scaptomyza flava

6b frass in black grains or strings => 7

7a frass in discrete grains; pupation in the leaf, in a, generally lower-surface, pupal chamber: Chromatomyia horticola

7b frass in clumps or strings; pupation outside the mine => 8

8a broad corridor or elongate blotch, with lateral extensions: Liriomyza xanthocera

8b normal corridor, often forming a secondary blotch towards the end: Liriomyza bryoniae

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

103 – Coleoptera

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

104 – Diptera

104a Cecidomyiidae: Contarinia nasturtii; Dasineura armoraciae

109 – powdery and downy mildews

109a Erysiphaceae: Erysiphe cruciferarum

109b Peronosporaceae: Hyaloperonospora cochleariae

110 – other causers

110a Fungi, Albuginaceae: Albugo candida

110b Fungi, Plasmodiophoraceae: Plasmodiophora brassicae