Plant Parasites of Europe

leafminers, galls and fungi

gallers on Stachys

Dichotomous table for gallers on Stachys

by Hans Roskam

1a On parts above ground => 2

1b Roots with small nodular or spindle-shaped swellings. S. sylvatica: Meloidogyne hapla

2a On inflorescences or flowers => 18

2b On vegetative plant parts => 3

3a Locally ± defined galls of stems or on leaves => 12

3b Malformations of shoot tips, on several leaves, or on expanded parts of leaf blades, often simultaneously on stems and other organs => 4

4a Malformations caused by animals => 6

4b Malformations caused by fungi with fruiting bodies at their surface => 5

5a The diseased basal- or more rarely stem leaves are paler and longer stalked than the healthy ones. On underside completely or extensively with scattered small brown sori, sometimes coalesced. S. officinalis & subsp. serotina, pradica: Puccinia betonicae

5b Similar, sometimes almost witches’ broom-like malformations on S. annua, recta: Puccinia vossii

5c Fungal down on the abnormally small, discoloured corolla. It consists of erect conidiophores that apically are branching dichotomously several times, each branch ending in a lemon-shaped conidium. S. palustris, recta: Peronospora jagei

6a Malformation of several leaves terminally on shoots => 7

6b Basal young shoots markedly stunted, conspicuously spongy, pale-green; leaf pairs densely clustered; leaf blades necrotic, similarly disfigured. S. arvensis, palustris, setifera: Ditylenchus dipsaci

7a Malformations caused by aphids and spittlebugs => 10

7b Malformations caused by gall mites or gall midge larvae => 8

8a Leaves clustered, bud- or rosette-like on main- or side shoots, also in leaf axils; galls lacking additional pubescence. Midge galls => 9

8b Stem terminally variously stunted, thickened and distorted; partially with ± excessive branching and leafiness; unfolding of leaves ± largely stunted; sometimes white-felt-like pubescent. Inflorescences and flowers, if present, severely disfigured. S. alpina, annua, officinalis & subsp. serotina, pradica, recta: Aceria solida

9a Inner leaves of end- or lateral buds severely stunted, not unfolding, often ± boat -shaped, bent and shrivelled; developing into a 15–35 mm long, pale, erect, irregular gall. Leaf blades of ± spreading leaves with cartilaginous, green-yellow roll of leaf margin. Larvae living also in disfigured inflorescences; dirty pale yellow to orange-coloured. S. alpina, palustris, recta, sylvatica: Wachtliella stachydis

9b Tip of main- and side shoots or axillary bud transformed into oval, converging loose leaf rosette. Containing several white larvae. S. alpina, palustris, recta, sylvatica: Wachtliella stachydis

10a Aphid galls => 11

10b Single or several terminal internodes usually stunted on one side, thickened and distorted. Stachys spp.: Philaenus spumarius

11a Leaves rolled inwards. Aphid 1.3–1.7 mm long, pale green. Siphunculi whitish with black tip. S. arvensis, cretica & subsp. salviifolia, officinalis, recta, sylvatica: Aphis stachydis

11b Leaves terminally clustered, rugose; transversely rolled downwards. Aphid about 1.5 (2.0) mm long, dark-green to dirty-yellow; siphunculi black. S. arvensis: Aphis gossypii

12a Galls on leaves => 15

12b Stem galls or galls exclusively on petioles => 13

13a Inducers inside malformations => 14

13b Stems, also basal parts of petioles ± bulging over a length of 20 (50) mm. S. officinalis, recta: Planchonia arabidis

14a Stem terminally almost globular; shoot tips atrophied and withering. Containing several larvae. S. alpina, officinalis, pradica, sylvatica: Thamnurgus kaltenbachii

14b Stem with several small pustules (procecidia: oviposition scars, not true galls) which wither after emergence of larvae. S. recta: Unidentified sawfly

15a Localised galls on leaf blades and sometimes additionally on stalks => 16

15b Petiole and leaf blade broadened at base, thickened, abnormally pubescent. S. officinalis: Unidentified gall midge

16a Bulge- or wart-shaped galls on leaf blade or on venation and stalks => 17

16b Leaf margin over ± large extent rolled upwards, irregular cartilaginous, pale-green. Containing orange larvae. S. alpina, palustris, recta, sylvatica: Wachtliella stachydis

17a Galls wart-like, less than 1 mm long, ± golden-yellow; many on underside of basal leaves, petioles and basal stem parts. S. officinalis: Synchytrium aureum

17b Small, weakly protruding, oblong-oval sori on main venation, petioles and young stems, bearing brown uredinia. S. annua, recta, sylvatica: Puccinia stachydis

18a Malformations limited to single or several flowers; axis of inflorescence usually not infected => 20

18b Malformation of complete or large parts of inflorescence => 19

19a Midrib ± stunted, thickened, distorted. Inflorescence compact, transformed into a rotund to oblong-oval ball. Calyx lobes often elongated. All infected green parts ± with white-felt-like pubescence. S. alpina, annua, officinalis & subsp. serotina, pradica, recta: Aceria solida

19b Flower buds ± clustered; unopened; only calyx swollen and enlarged. Corolla, stamens, pistil necrotic. Containing several orange-coloured larvae. S. alpina, palustris, recta, sylvatica: Wachtliella stachydis

20a Flower buds ± swollen, unopened. Midge galls => 21

20b Flowers outwardly hardly changed. Anthers at first swollen, soon destroyed by dark-violet, reticulate, later on dusting spores. S. alopecuros, maritima, officinalis, recta: Microbotryum betonicae

21a Galls thin-walled; internal mycelium absent => 22

21b Galls about 5–6 mm across. Inner wall with at first whitish, later on dirty grey, thick cotton-wool-like mycelium coating. Containing a single larva. S. recta: Asphondylia sp.

22a On S. officinalis. Buds distinctly swollen, unopened: Unidentified gall midge

22b On S. sylvatica. Larvae white, jumping: Ametrodiplosis crassinerva

Last modified 13.iv.2020