Plant Parasites of Europe

leafminers, galls and fungi

gallers on genus Gentiana

Dichotomous table for gallers on Gentiana

(incl. Gentianella, Gentianopsis)

by Hans Roskam

1a Galls on higher situated organs or on rosette leaves => 2

1b Rotund swellings, 2–3 mm long on root collar or stem base. G. campestris, etc.: cf. Smicronyx reichi

2a On higher situated parts or on single organs => 3

2b Leaves clustered, rosette-like. Gentianella amarella: Unidentified gall mite

3a On flowers => 7

3b On vegetative organs => 4

4a On shoot tips, axial parts of shoot or leaves => 5

4b Rotund ± one-sided ± bulging galls, up to 4 mm long, on axial parts of shoots, usually close to a node. On ± severely stunted stems symmetrical barrel- to spindle-shaped galls, up to about 8 (10) mm long. With a large chamber inside which may continue into the pith. Gentianopsis ciliata, Gentianella germanica: Smicronyx reichii

4c Stem, usually in lower half, with broad spindle-shaped one-sided flattened and often strongly deflected swelling, 6–10 mm long, containing the causer in the sharp bend below an arched scale. Gentianopsis ciliata, germanica: Planchonia arabidis

5a Malformations by other causers than aphids => 6

5b Malformations of shoots associated with atrophied flowers and discoloured leaves. Gentiana asclepiadea, cruciata: Aphis gentianae

6a Axial parts stunted and distorted on one side. Inserted leaves deflected and variously curled. Gentiana/ Gentianella spp.: Philaenus spumarius

6b Rarely developing aecia in spring on sometimes slightly bulging, oblong-oval areas on stems, flower peduncles, less so on petioles and leaf veins. Gentiana/ Gentianella spp.: Puccinia gentianae

7a Malformations caused by gall mites => 8

7b Flowers slightly disfigured, unopened. Gentiana pneumonanthe; Gentianella amarella, campestris, germanica: Dasineura gentianae

7c Capsule rarely swollen; containing a weevil larva or pupa. Gentianella amarella, campestris, germanica: Smicronyx reichii

8a Inflorescence transformed into a rosette of small leaves; flowers variously ± greened or leafy, occasionally filled with ± disfigured organs or developing further. Gentiana/ Gentianella spp.: Aculus kerneri and/or Eriophyes gentianae

8b Malformations on flowers with conspicuous wrinkling of calyx and corolla. Gentiana bavarica: Unidentified gall mite

Last modified 18.xi.2023