Plant Parasites of Europe

leafminers, galls and fungi

gallers on genus Draba

Dichotomous table for gallers on Draba

by Hans Roskam

1a On parts above ground => 2

1b Roots with ± expanded spindle-shaped, fleshy swellings, which contain densely crowded masses of minute spores in some cells. D. incana, muralis: Plasmodiophora brassicae

2a Malformations caused by fungi fructifying at surface of gall => 6

2b Malformations caused by animals, or by fungi fructifying inside galls => 3

3a Galls localised => 4

3b Infected shoots extensively disfigured, phyllanthy; leaves shorter and broader, ± disfigured; flowers often accumulated, tuft-like, atrophied or ± greened. D. aizoides, daurica, incana, muralis, nivalis, “rupestris”: Aceria drabae

3c On the same hosts and other Draba species in similar malformations. D. aizoides, daurica: Cecidophyes borealis

4a On leaves or stem parts => 5

4b Diseased shoots slightly swollen, slightly shorter than healthy ones; young seed soon distorted and filled with yellowish- to grey-violet sori. D. aizoides, alpina, incana: Thecaphora thlaspeos

5a Galls hardly 1 mm across but conspicuous, ± golden-yellow translucent; on leaves, stalks and even bracts; often coalescing into crusts. D. aizoides: Synchytrium drabae

5b Stalk of inflorescence shortened at tip, slightly thickened, curved. D. muralis: Cause unknown – ? dipteran

6a At first glossy, porcelain-like, with mealy dusty bulges on all green parts after rupturing. D. aizoides, cuspidata, hispanica, incana, sauteri: Albugo candida

6b Infected organs, mainly the upper stem parts, variously ± bulge-like, swollen and disfigured. Draba spp.: Puccinia drabae

6a Shoots etiolated. Underside of leaves often bearing dense, rotund sori. D. cinerea, daurica: Puccinia thlaspeos

6b Leaves with pales spots. Underside with a dense white down, consisting of erect conidiophores that apically are branching several times, each branch ending in a conidium. D. muralis, nemorosa: Hyaloperonospora drabae

6a Similar malformation. D. daurica, nemorosa: Hyaloperonospora norvegica

Last modified 17.xi.2023