Plant Parasites of Europe

leafminers, galls and fungi

gallers on Calamagrostis

Dichotomous table for gallers on Calamagrostis

by Hans Roskam

1a On panicles or flowers => 14

1b On vegetative parts => 2

2a Leaves with long stripes of smut or similar fungus patches on culms; shoot ± etiolated, usually remaining sterile => 12

2b Malformations caused by animals => 3

3a On shoot tips or leaves => 9

3b On culms => 4

4a Inducers in depressions on the outside of the culm underneath the sheaths => 6

4b Swelling of the shoot axis. Culm contains larva => 5

5a Culm above the second or third node with weak swelling, with one or several chambers one above the other, each contains a single larva. C. arundinacea, canescens, epigeios: Tetramesa calamagrostidis

5b Swelling absent, several chambers one above the other. C. epigeios: Tetramesa eximia

5c Slight, weak spindle-shaped swelling above a node. C. canescens: Tetramesa sp.

6a Galls on C. canescens => 7

6b On C. epigeios. Culm underneath the sheath above a node often with weak, slightly rimmed depressions on all sides. Larva orange-yellow: Lasioptera calamagrostidis

= Between culm and leaf sheath also live the orange-red cecidomyiid larvae of Asynapta thuraui which do not induce malformations

7a Depressions not or only slightly swollen at margins => 8

7b Saddle-shaped, sometimes brown, depressions shouldered at the ends by nodular thickenings. Gall 10–12 mm long, solitary or up to 4 on culm arranged upon one another or screw-like. Leaf sheath gaping. C. canescens, epigeios: Mayetiola bimaculata

8a Depressions about 3–4 mm long, ± covered with a thin, brittle, glossy black skin. Larva orange-yellow or brick-red. C. canescens: Hybolasioptera fasciata

8b Galls lacking black cover. Larvae in a weak depression beneath the leaf sheath on higher internodes:

a Larval spatula bifid. C. canescens, epigeios: Lasioptera calamagrostidis

b Larval spatula with only one tooth. C. canescens, epigeios: Mayetiola bimaculata

c Larval spatula with only one tooth. C. canescens: Mayetiola culacera or Mayetiola bifida

9a On shoot tips => 11

9b On leaf sheaths or leaf blades => 10

10a Upper leaf swollen, bladder-like, discoloured. Aphid up to 2 mm long, slim, yellow to brownish-green. C. arundinacea, epigeios, villosa: Laingia psammae

10b Leaf sheaths more or less swollen. Inside the sheaths are pale-yellowish aphids 1.5–2.5 mm long, and covered with wax powder. C. canescens, purpurea: Diuraphis calamagrostis

10c Leaf blades, mainly at base, often with several yellowish-green, later on reddish to dark violet, spindle-shaped rough swellings, smaller or up to 10 (15) mm long, slender cylindrical, often more prominent on underside. C. arundinacea, canescens, villosa: Subanguina graminophila

10d As inducer of similar, rotund-oval, up to 8 mm long and 2 mm broad galls on C. canadensis, epigeios has been suspected: Anguina graminis

11a Tip of shoot tuft-shaped, up to 35 mm long and 5 mm thick. Outer leaves with ± curled leaf blades, the inner ones lacking leaf blades; sheaths with their margins firmly appressed. Containing one to many white larvae with one-toothed spatula. C. canescens, epigeios, villosa: Mayetiola lanceolatae

11b Tip of shoot especially in underground shoots with shortened axis. Leaf sheaths widened and thickened. Leaves stunted, yellowish, often only ± scale-like. C. canescens: Unidentified chloropid

12a Spores solitary => 13

12b Spores in black balls with 1–4 (6), enveloped by many sterile cells. Long stripes of smut on leaf blades. C arundinacea, epigeios, neglecta, villosa: Urocystis calamagrostidis

13a Leaves with black patches of smut. Spores thick-walled, glabrous; 4–7 x 3–6 µm large. Patches mainly on culms, underneath sheaths. C. epigeios: Tranzscheliella hypodytes

13b Spore wall spiny or warty. Spores in the middle about (9) 14–16 (20) µm across. Patches on leaves, more rarely on sheaths. Closely related fungi, distinguished by their spore walls and sizes:

a Spore wall irregularly spiny; the appendages running into a discontinuous reticulate pattern at base. C. arundinacea, epigeios: Ustilago scrobiculata

b Spore wall with low rotund warts, up to 0.5 µm high, distinctly separated. C. canescens, lapponica, purpurea, stricta, villosa: Ustilago striiformis

c Spore wall with higher, conical warts about 1 µm high. C. canescens, epigeios, lapponica, purpurea, purpurea subsp. phragmitoides, stricta, villosa:
Ustilago calamagrostidis

13c Leaves with long stripes of smut. Uredinia mostly on upperside leaf, orange brown, with many capitate paraphyses. Telia on both sides, black, long covered by the epidermis; spores on a short pedicel, two-celled, top cell with the apical wall thickened. C. arundinacea, canescens, epigeios, pseudophragmites, varia, villosa: Puccinia pygmaea

13d Similar stripes of chlorotic tissue. C. epigeios: Puccinia striiformis

14a Complete panicle disfigured; flowers if weakly infected ± greened, if strongly infected often largely aborted, glumes markedly shortened, irregularly twisted and rolled; eventually bleached. C. arundinacea, canescens, epigeios, neglecta, purpurea incl. subsp. phragmitoides: Aceria tenuis

14b lower primordia with galls, containing many eelworms. C. ? canadensis, lapponica, Calamagrostis sp.: Anguina agrostis

Last modified 20.iii.2020