Plant Parasites of Europe

leafminers, galls and fungi

gallers on Sium

Dichotomous table for gallers on Sium

by (incl. Berula)

by Hans Roskam

1a On stems or leaves => 2

1b Fruit disfigured into a ± globular swollen gall. Containing a single orange-red larva. Berula erecta: Kiefferia pericarpiicola

2a Wart-shaped or bulge-like galls caused by fungi => 3

2b Leaf midrib stunted and deflected. Leaflets ± clustered, ± curled and locally deep green. Berula erecta; Sium. latifolium, sisarum: Philaenus spumarius

3a Spores inside galls => 4

3b Veins on underside of leaf with weak, ± rotund-oval bulges; midrib and stalk with broad spindle-shaped, stronger protruding swellings, bearing yellowish spermogonia and aecia. Berula erecta; S. latifolium: Uromyces lineolatus

3c Leaves with discoloured spots. On the underside is a whitish fungal down, consisting of erect, terminally repeatedly branching conidiophores, each branchlet bearing a globular conidium. S. latifolium: Plasmopara sii

4a Galls elongate spindle-shaped, vitreous, pale green; often adjoining venation; depending on the plant part only a few to many mm long. On all green plant parts; sometimes even on calyx and fruits. Within the tissue close to vascular bundle are many, ± rotund, often 60–70 µm large perennial (‘dauer’) spores. Berula erecta; Sium latifolium: Protomyces macrosporus

4b Only a few mm long, wart-shaped, usually many, at first colourless-whitish, then dull brown galls, which cluster on leaf blade, -midrib, -stalk and stem may cause additional malformations. Inside nutritive cell several, about 20–35 x 15–30 µm large perennial (“dauer”) spores. Berula erecta; S. latifolium: Physoderma vagans

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