Plant Parasites of Europe

leafminers, galls and fungi

gallers on Primula

Dichotomous table for gallers on Primula

by Hans Roskam

1a On parts above ground => 2

1b On roots or root collar => 3

2a Roots with ± elongated, nodular swellings. P. auricula, carniolica: Meloidogyne hapla

2b Short, strongly thickened and banded shoots on root collar. P. juliae: Rhodococcus fascians

3a On inflorescences or flowers => 9

3b On leaves => 4

3c Whole plant disfigured, covered by a down of branched conidiophores. P. acaulis, auricula, elatior, veris: Peronospora oerteliana

4a Leaf blades strongly curled, margin rolled, warts, pads, bulges or spongy, swollen galls on leaves and stems => 8

4b Malformation usually of several rosette leaves caused by the perennial mycelium of monoecious rust fungi. Leaves paler and slightly longer stalked than healthy ones, rigidly erect, soon covered with sori. Primula spp.: Uromyces primulae-integrifoliae

5a Warts, pads or bulges caused by fungi => 8

5b More or less expanded parts with spongy swellings; also curling of leaf blades or rolling of leaf margin => 6

6a Leaf blades curved, curled or margins rolled => 7

6b Whole plant ± stunted. Leaves shortened, especially swollen at base and at veins. Often with various swellings also on inflorescence. Flowers variously swollen and leafy. Primula spp.: Ditylenchus dipsaci

7a Leaf margin narrowly rolled upwards. P. auricula: Unidentified gall mite

7b Leaf blades to large extent often obliquely rolled downwards over the tip, hunched up and arched, dark green close to infestation. A single or several froth-covered nymphs on underside. Primula spp.: Philaenus spumarius

8a Basal leaf parts and venation with many solitary or variously joined, multicellular golden-yellow warts, less than 1 mm long. P. elatior, veris: Synchytrium aureum

8b Leaf underside with rotund aecia bearing pads, on veins ± elongated, yellow, sometimes weakly swollen. Aecia cup-shaped with deflected, lacerate border. P. acaulis, elatior, grandiflora, veris: Puccinia primulae

9a Ovary moderately to belly-like swollen. Seed primordia swollen => 11

9b Malformation of almost all flower parts => 10

10a Flowers variously disfigured. Corolla often greened; also anthers and pistil variously greened; leafiness. These malformations also on plants which bear spongy bulgings on other parts. P. denticulata & var. cashmeriana, florindae, rosea, veris: Ditylenchus dipsaci

10b Calyx tube-shaped elongate, sometimes inflated. Corolla calyx-like transformed, green. Ovary swollen, protruding from flower; seed primordia transformed into minute leaf-like structures. P. florindae: Subanguina klebahni

11a Seed primordia at first hypertrophied, later on filled with masses of blackish, irregular rotund to oblong spore balls. Ovary slightly swollen. Infestation of flowers inconspicuous from the outside. P. acaulis, elatior & subsp. intricata, veris & subspp. canescens + columnae + macrocalyx, vulgaris: Urocystis primulae

11b With similar biology on P. farinosa, stricta, veris & subsp. columnae: Urocystis primulicola

Last modified 10.iv.2020