Glyceria, sweet-grass

Larvae of a number of species of Chironomidae (non-biting midges) live in tunnels in decaying leaf sheaths under water. Their tunnels are open at both ends, and the larvae feed on particles they obtain from a water current they create in the tunnels. They do not feed on tissues of their “host plant”, therefore are no miners, and are not treated here.

1a larva a maggot; pupation either within or outside the mine => 2

1b larva with feet and chitinised head; pupation outside the mine => 11

1c gallen etc => 100

2a larva: mandible with 1 tooth; at the start of the mine (often within a leaf sheath) an egg shell at the outside => 3

2b mandible with at leat 2 teeth; no egg shell visible => 4

3a larvae from Mayi: Hydrellia griseola

3b larvae in April: Hydrellia thoracica

4a larva: cephalic skeleton of Phytomyzinae-type; puparium in the mine => 5

4b cephalic skeleton of Agromyzinae-type; pupation outside the mine => 7 *

5a puparium metallic black; spiracula don’t penetrate the epidermis: Cerodontha pygmaea

5b puparium orange brown; front spiracula penetrate the epidermis => 6

6a puparium ventrally with a broad dark brown length line: Chromatomyia fuscula

6b puparium ventrally uniformy light brown: Chromatomyia nigra

7a larva: front spiracula strongly enlarge, disc-shaped; only on Glyceria maxima: Agromyza alunulata

7b front spiracula normal; possibly also on other Glyceria-species => 8

8a larva: ventrally behind the mandible a field of broad, small spines: Agromyza nigrella

8b no such field present => 9

9a larva: mandible with 3 teeth: Agromyza lucida

9b mandible with 4 teeth => 10

10a larva: rear spiracula touch each other (occurrence on Glyceria dubious): Agromyza albipennis

10b rear spiracula separated by at least their own diameter: Agromyza nigripes

11a mine long and/or broad => 12

11b mine quite small => 17

12a mine broad, yellow-white, mainly in the leaf tip: Elachista pomerana

12b mine long and narrow => 13

13a larva: with one or more length lines => 14

13b no length lines => 15

14a larva: whitish with 4 reddish-brown length lines: Sedina buettneri

14b yellowish with a brown dorsal length line: Nymphula nitidulata

15a mine inflated: Donacaula forficella

15b mine flat => 16

16a frass in a single line: Elachista poae

16b frass, at least in the oldest part of the mine, in two or more parallel lines: Elachista apicipunctella

17a larva with length lines: Orthotelia sparganella

17b no length lines => 18

18a larva: pinacula colourless (the bases of the setae themselves are black): Cnephasia incertana

18b pinacula black: Cnephasia asseclana

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

102 – Acari

102a Eriophyidae: Aceria tenuis

104 – Diptera

104a Cecidomyiidae: Octodiplosis glyceriae

105 – Hemiptera

105a Aphididae: Laingia psammae

107 – rust fungi

107a Pucciniaceae: Puccinia coronata, graminis, striiformis

108 – smut fungi

108a Ustilaginaceae: Tranzscheliella hypodytes; Ustilago davisii, filiformis

108b Ustilentylomataceae: Ustilentyloma fluitans

109 – powdery and downy mildews

109a Erysiphaceae: Blumeria graminis

109b Peronosporaceae: Sclerophthora macrospora

110 – other causers

110a Fungi, Ceratobasidiaceae: Ceratorhiza rhizodes

110b Fungi, Clavicipitaceae: Claviceps purpurea

110c Fungi, Physodermataceae: Physoderma gerhardtii

110d Fungi, Plasmodiophoraceae: Sorosphaera radicalis

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