Avena, oat

fam. Poaceae

1a fleck mine => 2

1b gallery or blotch => 3

1c galls, etc => 100

2a no longer applies

2b case brown, trivalved, on cultivated Oat: Coleophora ciconiella

3a larva with feet and chitinised head (Elachistidae) => 4

3b larva a maggot => 7

4a larva grey-green Elachista bedellella & E. pullicomella

4b larva dirty white – yellowish => 5

5a larva: head pale brown: Elachista griseella, E. pomerana & E. subnigrella

5b head dark brown to black => 6

6a mine strongly inflated; larva: pronotum with a pair of samll spots: Elachista albifrontella

6b mine almost flat; pronotum marked more strongly: Elachista stabilella

7a at the start of the mine (not infrequently within the leaf sheath) at the outside an egg shell; larva: mandible with 1 tooth: Hydrellia griseola

7b no egg shell visible; mandible with ≥ 2 teeth => 8

8a larva: cephalic skeleton of Agromyzinae-type; pupation usually outside the mine * => 9

8b cephalic skeleton of Phytomyzinae-type; pupation within or outside the mine => 12

9a larva: bands of spines over the segments unusually wide; abdomen segment 8 dorsally spinulose over its entire width: Agromyza nigrociliata

9b band of spines normal in width; segment 8 dorsally spinulose only anteriorly and posteriorly => 10

10a rear end of larva cut off obliquely; larvae often communal; mine greenish: Agromyza nigrella

10b rear end cut off at right angle; larvae usually solitary; mine whitish => 11

11a larva: mandible with 2 teeth: Agromyza rondensis

11b mandible with 3 teeth: Agromyza ambigua

12a pupation outside the mine => 13

12b puparium within the mine => 14

13a larva and puparium with a transverse row of long, spine-like papillae on each segment: Pseudonapomyza atra

13b no such spines: Liriomyza flaveola

14a front spiracula of the puparium penetrating the epidermis => 15

14b puparium not in connection with the outside world => 17

15a puparium: rear spiracula fang-shaped, anchoring the puparium in the leaf parenchyma: Chromatomyia milii

15b rear spiracula normal => 16

16a puparium monochromous orange pbrown; front spiraculum indistinctly bifid: Chromatomyia nigra

16b puparium yellow ro ornage-brown, with a dark ventral length band; front spiraculum fist-shaped: Chromatomyia fuscula

17a larva: rear spiraculum with 11-16 papillae; puparium in the leaf sheath: Cerodontha denticornis

17b rear spiraculum with 6 papillae at most; puparium in the leaf blade => 18

18a 2-4 larva in a mine; puparia anchored in the mine by a silken thread => 19

18b larva solitary; puparium loose in the mine: Cerodontha superciliosa

19a larva: the black warts at the outside of the rear spiracula small, without a “root”: Cerodontha incisa

19b these warts large, with a deep “root”: Cerodontha pygmaea

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: Anguina tritici; Ditylenchus dipsaci; Subanguina radicicola

101b Heteroderidae: Heterodera avenae

102 – Acari

102a Eriophyidae: Abacarus hystrix; Aceria tenuis

102b Tarsonemidae: Steneotarsonemus graminis, spirifex

104 – Diptera

104a Cecidomyiidae: Haplodiposis marginata; Hybolasioptera fasciata; Mayetiola avenae

104b Chloropidae: Chlorops pumilionis; Oscinella frit

107 – rust fungi

107a Pucciniaceae: Puccinia albigensis, coronata, graminis, striiformis

108 – smut fungi

108a Ustilaginaceae: Ustilago avenae, hordei, striiformis

109 – powdery and downy mildews

109a Erysiphaceae: Blumeria graminis

109b Peronosporaceae: Sclerophthora macrospora

110 – other causers

110a Fungi, Clavicipitaceae: Claviceps purpurea

* See also the key to the grass-inhabiting Agromyza larvae.

Not included in the key: Chromatomyia horticola; Coleophora ornatipennella; Liriomyza orbona, Liriomyza trifolii; Ochsenheimeria taurella; Pseudonapomyza atratula (inadequately described).

20/02/2017