Plant Parasites of Europe

leafminers, galls and fungi

gallers on Spergula

Dichotomous table for gallers on Spergula

by Hans Roskam

1a On parts above ground => 2

1b Roots with nodular to slender spindle-shaped swellings, bearing some side roots. S. arvensis: Meloidogyne hapla

1c Roots inside with giant cells, outwardly hardly changed or with excessive development of side roots above the infestation site. S. arvensis: Heterodera schachtii

2a Malformations of expanded parts of plant => 3

2b Local, rotund- to oblong-oval pads, sometimes resulting in distortions, up to about 5 mm long, occasionally slightly thickened, often yellow-margined, soon covered with 2-celled brown telia.  S. arvensis, morisonii, pentandra: Puccinia arenariae

3a Malformations caused by fungi which fruit at surface => 6

3b Malformations caused by animals => 4

4a Parasites live at surface of malformations => 5

4b Young plants completely stunted. Stem severely stunted, especially spongy, swollen at base. Basal- and gall-bearing leaves similarly disfigured. Containing many eelworms. S. arvensis, pentandra, morisonii: Ditylenchus dipsaci

5a Stem terminally stunted; organs clustered, with reduced and bent leaves and partially also with stunted, disfigured flower buds; flowers a little opened, ± greened and leafy. S. arvensis, pentandra: Inducer unknown – ? gall mite

5b Gall-like twisting, bending or S-shaped or right-angled distortion of ± discoloured leaves. S. arvensis: Taeniothrips atratus

6a Internodes of strongly infected young plants shortened, slightly thickened, sometimes curved. Leaf whorls accumulated; leaves stunted, pale green, slightly swollen as result of defective differentiation of tissue. The usually many diseased flower buds ± bloated, globular. All diseased parts soon covered with a loose down of branched conidiophores, partially containing oospores. S. arvensis: Peronospora obovata

6b Similar malformations on S. morisonii, pentandra: Peronospora vernalis

Last modified 24.v.2020