Plantparasieten van Europa

bladmineerders, gallen en schimmels

gallers on genus Erysimum

Dichotomous table for gallers on Erysimum

by Hans Roskam

1a On parts above ground => 5

1b On roots or on root collar => 2

2a Fleshy thickened galls on main- and side roots => 3

2b Galls on root collar, ± globular, about 6 mm across, usually single, rarely 2–3 (4). Each chamber contains a white larva. E. cheiri, cheiranthoides, hieraciifolium: Ceutorhynchus assimilis

= “Leafy galls” caused by the polyphagous bacterium Rhodococcus fascians have been reported on root collar of Erysimum allionii

3a Galls nodular, spindle-shaped or cylindrical; larval chamber lacking => 4

3b Galls on root collar or on main root, occasionally single and usually 4–5 mm across, often with several to many coalesced into conspicuous, sometimes irregular globular, mainly ± deeply subdivided, sausage-shaped clusters. Each chamber containing a single yellowish-white larva. E. cheiranthoides, pseudorhaeticum: Ceutorhynchus plumbeus

4a Small, spindle-shaped or nodular galls, up to 4 mm long, on side roots bearing, several adventitious roots. E. cheiranthoides: Meloidogyne hapla

4b Conspicuous, succulent, spindle-shaped to cylindrical swellings on main- and side roots. Inside the tissue are many cells containing dense masses of minute spores. Erysimum spp.: Plasmodiophora brassicae</p>

5a Malformations locally ± defined => 6

5b Stem, young shoots and also axis of inflorescence usually with expanded, conspicuous, often distorted swellings, soon covered with a down of branched conidiophores. Flowers of diseased inflorescences severely stunted. Leaves of axillary shoots if infected early, ± spoon-like arched, thickened, brittle, pale green; with a dense down of conidiophores on underside. Erysimum spp.: Hyaloperonospora parasitica

6a Malformations with sori fruiting at surface => 13

6b Malformations caused by animal causers => 7

7a On inflorescences, flowers or fruits => 12

7b On vegetative parts => 8

8a On shoot tips or leaves => 10

8b On shoot axial parts => 9

9a Swelling usually in axis of inflorescence, slightly protruding, oblong; inflorescence ± broom-like disfigured. In pith is a long tunnel containing a single beetle larva. E. cheiranthoides, hieraciifolium, odorarum: Ceutorhynchus sp.

9b Basal parts of young plants spongy. Internodes ± markedly shortened; petiole and midrib thickened, ± curved. Gall surface undulately wrinkled. Inside the soon necrotic tissue are many eelworms. Erysimum spp.: Ditylenchus dipsaci

9c Conspicuous multi-locular galls, partially slightly irregular bulging. Each chamber containing a single yellow-red larva. E. cheiranthoides, crepidifolium, canescens, hieraciifolium, odoratum, repandum: Bayeriola erysimi

9d Similar gall, only known from Greece. E. cheiranthoides, graecum, odoratum: Janetiella fortiana

10a Malformations caused by aphids or spittlebugs => 11

10b Leaves clustered on shoot tip or young inflorescences and transformed into a ± fleshy to spongy gall. E. cheiranthoides, comatum, diffusum, hieracifolium: Contarinia nasturtii

11a Shoot tips ± stunted, over variable length bearing ± stunted, often rolled leaves. E. cheiranthoides, crepidifolium: Lipaphis erysimi

11b Upperside of leaves, which are rolled upwards into compact tubes and usually become reddish to dirty purple. Erysimum spp.: Pseudobrevicoryne erysimi

11c Shoot axis usually stunted on one side and curved. Leaves with several converging, ± curled, nest-like. Infected peduncle of inflorescence severely stunted; flowers distorted, clustered ball-like. E. cheiranthoides: Philaenus spumarius

12a Flower buds swollen especially at base, unopened. Contain several yellow jumping larvae. E. cheiranthoides, comatum, diffusum, hieracifolium: Contarinia nasturtii

12b Swollen flower bud containing several non-jumping gall midge larvae. Attacked flowers stop development and do not produce pods. E. graecum: Jaapiella erysimicola

12c Flowers greened, leafy, abnormally haired, in ± dense clusters. E. angustifolium, canescens, cheiranthoides, diffusum, hieracifolium: Aceria drabae

13a Sori white => 14

13b Sori rust- to dark brown. In many rotund, almost aecia-like rupturing, small groups over the complete underside of stem leaves of usually non-flowering plants. Leaf blades ± disfigured, often smaller, slightly thickened and discoloured. E. cheiranthoides, hieraciifolium: Puccinia holboelli

14a Young shoots often infected to great extent. Diseased internodes shortened, conspicuously thickened and the terminal part especially often strongly curved; inserted younger leaves severely stunted, distorted and twisted. Infected parts soon with extensive mealy dusting down of branched conidiophores. Erysimum spp.: Hyaloperonospora cheiranthi

14b Sori in loose down, consisting of branched conidiophores. Strong infestation of young fruits, and axial parts results in conspicuous, even spiral twisting associated with swellings. Erysimum spp.: Peronospora erysimi

14c Sori dense, at first closed, later on rupturing and with mealy dusting, in ± expanded pads on all green parts, also on flowers Erysimum spp.:Albugo candida

Laatste bewerking 17.xi.2023