Plant Parasites of Europe

leafminers, galls and fungi

gallers on Hirschfeldia

Dichotomous table for gallers on Hirschfeldia

by Hans Roskam

1a On parts above ground => 2

1b Main- or side roots with conspicuous swellings, usually more than 5 mm long, spindle-shaped to cylindrical, succulent, compact. H. incana: Plasmodiophora brassicae

1c Much smaller swellings, only 3–4 mm long. H. incana: Meloidogyne hapla

2a On shoot tips, leaves, flowers or fruits => 4

2b On stems, petioles or midrib => 3

3a White sori of variable size, at first closed and glossy, porcelain-like, later with mealy dusting after rupturing, on ± swollen and disfigured green parts. H. incana: Albugo candida

3b Midrib of leaf or stem with swellings 12–15 (20) mm long, also deep green inside, one-chambered, spindle-shaped. Containing a single larva. H. incana: Ceutorhynchus chalybaeus

4a On flowers => 6

4b On shoot tips or leaves => 5

4c Silique swollen, containing a single orange midge larva. H. incana: Asphondylia stefanii

5a Axis, especially of developing axillary buds, severely stunted, between the bases of clustered leaves, especially at thickened bases, are several whitish to lemon-yellow jumping larvae. H. incana (incl. adpressa): Contarinia nasturtii

5b Leaf blades of young rosette leaves in variable expansion rolled upwards undulate or bent, usually pale green. Older leaves with variously expanded pale green, often deflected, folds. On upper side or underside in the galls are colonies of mealy dusted aphids H. incana: Brevicoryne brassicae

6a Flowers swollen, unopened; calyx enlarged, corolla and anthers necrotic; anthers and ovaries stunted and thickened. Midge galls => 7

6b Flowers conspicuously disfigured; calyx and corolla strongly enlarged, thickened and greened; stamens ± aborted; ovaries swollen, wide tube-shaped; partially with white sori, at first glossy, porcelain-like, later on with mealy dusting. H. incana: Albugo candida

7a Larvae with several, whitish- to lemon yellow, jumping. H. incana: Contarinia nasturtii

7b Several larvae, non-jumping when mature. H. incana: Gephyraulus raphanistri

7c Silique swollen, containing a single orange midge larva. H. incana: Asphondylia stefanii

Last modified 15.v.2020