Plant Parasites of Europe

leafminers, galls and fungi

gallers on Moehringia

Dichotomous table for gallers on Moehringia

by Hans Roskam

1a On parts above ground => 2

1b Root with lentil-size swellings. M. trinervia: Meloidogyne hapla

2a On inflorescences or flowers => 11

2b On vegetative parts => 3

3a Several leaves with nearly similar malformations at shoot tips or all over the plant => 5

3b Locally restricted galls on leaves or stems => 4

4a Many yellow translucent multi-cellular warts, less than 1 mm long, on basal leaves and stem parts. M. trinervia: Synchytrium aureum

4b Rotund, sometimes depressed on upperside, yellowish to brown-yellow, on underside, pad-like swellings on leaves, or, elongate in direction of organ development, sometimes distorted bulges on axial parts up to 6 mm long. M. diversifolia, muscosa, tenuifolia, trinervia: Puccinia arenariae

5a Animal causers => 7

5b Caused by fungi fruiting at surface => 6

6a Systemically infected shoots longer and lanky; rigidly erect; leaves often longer stalked; small, pale, sometimes deflected at margin, with a dirty-white to grey down of branched conidiophores on underside. M. ciliata, trinervia: Peronospora arenariae

6b Similar malformations, usually on many shoots of a plant; on all green parts, especially on leaf underside, with many loosely arranged yellow sori. M. trinervia: Melampsorella caryophyllacearum

7a Caused by aphids or spittlebugs => 9

7b Caused by gall mites => 8

8a Leaves clustered at main- and side shoots, disfigured; flowers greened or double, also developing further. M. ciliata, lateriflora: Aceria moehringiae

8b Leaves wrinkled, clustered ball-like at shoot tip; development stunted; development of flowers suppressed; normal flowers exceptional. M. trinervia: Cause unknown – ? gall mite

9a Caused by aphids => 10

9b Shoot axis stunted, with local, sometimes almost facultative, nest-like clustered, deflected, ± curled, partially deep green leaves. M. trinervia: Philaenus spumarius

10a Leaves pod-like folded upwards, violet-marbled, inside weakly pubescent. M. trinervia: Brachycolus stellariae

10b Leaves terminally accumulated, reduced, sometimes discoloured, undulate curled, bent upwards, also deflected, sometimes slightly more pubescent. Aphid reddish to dark brown. M. trinervia: Myzus certus

11a Often largely leafy flowers associated with excessive branching. M. ciliata, lateriflora: Aceria moehringiae

11b In outwardly normal flowers the anthers are stunted, swollen and soon filled with a dusty violet spore mass. M. lateriflora: Microbotryum violaceum

Last modified 17.iv.2020