Plant Parasites of Europe

leafminers, galls and fungi

gallers on Chenopodium

Dichotomous table for gallers on Chenopodium

(incl. Blitum, Chenopodiastrum, Dysphania, Lipandra, Oxybasis)

by Hans Roskam

1a On parts above ground => 3

1b On roots => 2

2a Roots with small, nodular or spindle-shaped, compact swellings, up to about 4 mm long. Chenopodium album; Dysphania ambrosioides; Lipandra polysperma: Meloidogyne hapla

2b Outside of root unchanged, inside with giant cells. C. album: Heterodera schachtii

= On Oxybasis glauca the clover cyst eelworm Heterodera trifolii has been recorded

2c Main root close to ground surface with conspicuous, easily rupturing, 30 to 80 mm long, 5–6 mm thick, beet-like thickening, with a broad, elongate cavity usually containing several larvae. Chenopodium spp. s.l.: Bothynoderes affinis

3a Leaves with abnormal pubescence or with down-like sori of fungi => 12

3b Malformations not conspicuously pubescent or without down-like sori => 4

4a Extensive malformations caused by aphids, spittlebugs or psyllids => 9

4b Causers belong to other groups => 5

5a Single galls pearl-like, on leaves, often also on stems; sometimes, on greatly disfigured organs, coalescing into ± expanded ridge- or crust-like groups => 8

5b Malformations extensive, of indefinite shape => 6

6 Galls predominantly on stem parts => 7

6b Infected shoots or complete plants growing abnormally, ± crippled, almost witches’ broom-like. Leaves ± erect and distorted, narrower than those on healthy plants. Flower buds slightly inflated, at first unopened, often densely aggregated, their ovaries soon filled with a grey-brown, later on dusty spore mass. Chenopodium album, strictum; Dysphania ambrosioides: Thecaphora leptideum

7a Shoot axis, depending on grade of infestation, ± bulge-like swollen over various lengths; with rotund-oval, rimmed depressions containing causer. Chenopodiastrum hybridum: Planchonia arabidis

7b Galls broad spindle-shaped or narrowing barrel-shaped; up to hazelnut-size. Inside are several oblong larval chambers. Each chamber contains a single yolk-yellow or red larva. C. album: Aplonyx chenopodii

7c Stem parts of young plants distinctly shortened, spongy, swollen. Inserted leaves with shortened, thickened stalks and veins, leaf blades variously disfigured. Chenopodium album, foliosum, Lipandra polysperma: Ditylenchus dipsaci

= Terminally bushy, compact plants of Chenopodiastrum murale with oblong, slightly spindle-shaped stem galls with an expanded frass-containing pith channel. Cf. Scrobipalpa obsoletella

8a Leaves and stems, rarely also perigone, with 1–2 mm long or more expanded, multicellular, wart-like, ± hemispherical, watery- or yellow-green, curly galls which in the case of more dense infestation, join into larger bulges on the often conspicuously distorted axial leaf parts or margins, as well as on stem parts. Chenopodium spp. s.l.: Physoderma pulposum

8b Single galls hardly 1 mm across, golden-yellow translucent, on underside of basal leaves, their stalks and stems. Chenopodium album, Lipandra glauca, Oxybasis rubra: Synchytrium aureum

9a Malformations contain aphids => 11

9b Malformations caused by psyllids or spittlebugs => 10

10a Leaf blades with irregular leaf folds, caused by froth-covered nymphs of psyllids. Chenopodium spp. s.l.: Heterotrioza chenopodii/p>

10b Leaf blades variously ± nest-like deflected, hunch-backed curled, dark green close to the froth-covered nymph. C. bonus-henricus, etc.: Philaenus spumarius

11a eaves on the ± shortened shoot tips converging, their leaf blades stunted, variously also deflected over their tip; infected inflorescences clustered, globular. Aphid black. Chenopodium spp. s.l.: Aphis fabae

11b Leaves upwardly folded along midrib or rolled, often distinctly thickened and severely discoloured. Aphid about 1.5 mm long, green, conspicuously frosted with white powdery wax. Chenopodium spp. s.l.: Hayhurstia atriplicis

12a Leaves lacking bladder-like swellings, abnormally pubescent. Hairs simple, not branched fork-like. C. album: Unidentified gall mite

12b Leaf blade with ± expanded, sometimes considerably, pale green, occasionally violet discoloured, bladder-like, partially distinctly thickened swellings, on underside a dense dirty-violet down of multiple fork-like branched conidiophores. Fungi belong to the species complex of Peronospora farinosa

Last modified 26.v.2020