Plant Parasites of Europe

leafminers, galls and fungi

gallers on Lolium

Dichotomous table for gallers on Lolium

by Hans Roskam

1a On above-ground parts => 3

1b On roots => 2

2a Roots often with many slender galls, up to about 5 mm long and 0.5–4 mm thick, usually bent or twisted half screw-like. L. perenne: Subanguina radicicola

2b Roots from the outside hardly changed, inside with giant cells, temporarily occupied by white to brown, about poppy-seed size cysts. Lolium spp.: Heterodera avenae

3a On inflorescences, flowers or fruits => 8

3b On culms, shoot tips or leaves => 4

4a Malformations on culms, shoot tips or leaves => 5

4b Complete plant stunted, disfigured, often additionally leaf-like, shoots often reddish discoloured, especially thickened close to ground. Leaves shortened, bent and rugose. L. multiflorum, perenne: Ditylenchus dipsaci

4c Growth compact and stunted, spikes disfigured, however, many shoots remain healthy. L. perenne: Steneotarsonemus spirifex

5a Malformations on leaf blades => 7

5b Malformations on culms or shoot tips => 6

6a Saddle-shaped depressions, about 10–12 mm long, elongated, raised at the ends above the terminal node, covered by slightly swollen leaf sheaths. Each gall containing a brick-red larva. L. temulentum: Haplodiplosis marginata

6b Occasionally on L. multiflorum, perenne occurring as various malformations: Oscinella frit

6c Terminal tuft of imbricate leaves, discoloured, stem not swollen. L. perenne: Tetramesa sp.

6d Whitish, at surface yellowish or brownish patches, which envelope a large area of the upper part of stem, of which further development is stunted. Node of stem rarely swollen, encircled by fungus stroma, yellowish when mature; several nodes may be affected; flowering stunted; stroma contains narrow asci and filamentous spores. L. multiflorum, perenne: Epichloë typhina

7a Leaves rolled, plant ± severely stunted. L. multiflorum, perenne: Diuraphis frequens

7b Leaf blade, sheath and occasionally culm with long parallel stripes caused by smut. L. perenne: Urocystis bolivarii

7c Spores solitary, brown-black, globular or rotund-oval. L. perenne: Ustilago striiformis

7d Long conspicuous stripes on chlorotic leaf tissue caused by rust fungus. L. perenne: Puccinia striiformis

8a Malformations of inflorescences or their stalks => 9

8b Yellow larvae live gregariously in the inflorescences. L. perenne: Contarinia lolii

8c Ovaries distinctly swollen, transformed into a ± egg-shaped, acuminate structure, filled with a yellowish to yellowish-brown spore mass, foul-smelling when fresh. Lolium multiflorum, perenne, remotum, rigidum, temulentum: Tilletia lolii

9a Spikelets developing further, floral parts variously greened or leaf-like, in other cases bleached. L. perenne: Aceria tenuis

9b Lateral spindle-shaped swelling at base of inflorescence stalk. L. perenne: Tetramesa sp.

Last modified 16.vii.2020