Plant Parasites of Europe

leafminers, galls and fungi

gallers on genus Apium

Dichotomous table for gallers on Apium

(Incl. Helosciadium)

by Hans Roskam

1a On parts above ground => 2

1b Roots with nodule-shaped swellings, occasionally clustered, ± curved. A. graveolens: Meloidogyne hapla

= Almost coral-like thickenings on roots of etiolated plants are caused by the ectoparasitically living, usually non-cecidogenic, needle eelworm Paralongidorus maximus. Also reported are the dagger eelworm Xiphinema sp.

2a Curl of leaves caused by aphids or cercopids => 7

2b Malformations caused by eelworms or fungi => 3

3a Bulge-like swellings caused by fungi with fructifications on surface => 6

3b Galls without fruiting bodies on surface => 4

4a Galls only a few mm long => 5

4b Mainly base of petioles spongy, swollen. Galls wrinkled. Leaf blades ± yellowing. Upper part of tubers sometimes with ± expanded protrusions, at first wart-like, then penetrating deeper, soon decaying, eelworm-rich infestation sites. A. graveolens: Ditylenchus dipsaci

5a Leaf blade with flat, pin head sized galls, at first white, then yellowish, eventually brown; also on petioles and stems, there occasionally coalescing into ± spindle-shaped bulges; sometimes even on rays of (partial) umbels as well as ovaries. A. nodiflorum: Buerenia inundata

5b In similar small pustules on leaves developing on A. nodiflorum, repens:
Entyloma helosciadii

5c Petiole and leaf veins, and stem with oblong-oval flat bulges, up to 3 mm long, pale green, later on browned. A. inundatum nodiflorum, repens: Physoderma vagans

5d Leaves with small hard pustules, less than 0.5 mm across. Apium spp.: Synchytrium aureum

6a Petiole, rachis, or leaf veins with spindle-shaped, distinctly pad-like arched, yellowish to brownish bulges, usually on underside. Aecia densely placed, cup-shaped, with distinctly protruding, frayed border; spermogonia countersunk. A. graveolens, nodiflorum: Uromyces lineolatus

6b Yellowish, slightly swollen bulging, rotund- to oblong-oval pads, occasionally on the venation, bearing spermogonia as well as aecia on underside. A. graveolens, prostratum: Puccinia apii

7a Large parts of leaf blade ± nest-like deflected; rachis shortened; leaflets close to the froth-covered nymph curled and intensely green. A. graveolens: Philaenus spumarius

7b Leaf blades slightly deflected; rachis shortened; causing complete leaf blade to become compact, ± depressed, with black aphids on underside. A. graveolens: Aphis fabae

Last modified 17.xi.2023